Corn Chips, Garnished and Sauced. Loco? Right.

“IT’S everything at once,” Abraham Hernandez said as he jabbed a fork into a cardboard serving boat layered with salsa verde-flavored Tostitos corn chips and topped with, among other items, shaved jicama, pickled pig skins and stumpy tamarind candies. “The chips are crisp, the toppings are soft, the flavors are sweet and hot and salty.”

“In Mexico, they’re smart,” said Berta Nava, who assembled the dish, called Tostilocos, that Mr. Hernandez was eating at Nava’s Bakery and Comida Mexicana, her family snack shop here. “They take a food, a bag of chips, anything and say: ‘What else? What else can we do?’ ”

As if to illustrate her answer, she went to work on another order of Tostilocos, which she garnished with all those toppings as well as soy-coated peanuts and chopped cucumbers. She then drenched the whole shebang in lime juice, hot sauce and chamoy, a magenta-colored sauce made with pickled fruits and chiles.

“You can use any base,” she said. “Most people start with Tostitos. I can do Cheetos, the flaming hot kind, and Churritos, too.” (Churritos are stick-shaped extruded masa snacks, flavored with chile and lime.) “I can do anything you want loco.”

In Spanish loco means crazy, an apt description of these chip dishes.

Tostilocos were conceived across the Mexican border about 10 years ago, probably in Tijuana. Now variations on this modern folk food are gaining popularity here and in other stateside communities where Mexican immigrants settle. American companies, working both sides of the border, have recently begun to commodify the dish, and a few relatively upscale restaurants are also interpreting it.

Ms. Nava learned to make and eat Tostilocos 40 miles south of Escondido in Tijuana, where service is often less formal. Many vendors there just slit open a bag of chips and ladle on ingredients until the plastic sleeve threatens to collapse beneath the weight of what Derrik Chinn, a proprietor of a tourist service in Tijuana, called a “fruit-nut-nacho-lard salad.”

Today Tostilocos, also known as Tosti locos, are a baseline Tijuana street food, often consumed on the go, as sauce leaks from a split in the bag and drips Rorschach patterns onto the pavement. Asked where he liked to eat Tostilocos, Carlos Ivan, a cabdriver, smiled and said, “I eat them in the street, when I’ve been drinking cerveza or tequila.”

At soccer games and wrestling matches, Tijuana vendors work the crowds with plastic flats of preassembled Tostilocos bags stacked on their heads. Tostilocos are a standard at city parks and are popular in Tijuana beach communities. Some movie theater operators in northern Mexico park tricked-out Tostilocos carts, outfitted with chilled condiment wells, in their lobbies.

Unlike tacos or tamales, Tostilocos require no heat source to cook them or keep them warm. And start-up costs are low. Vendors stock up for the night with 24-packs of snack chips and $10 worth of vegetables and condiments.

On Saturday evenings in Tijuana, when the bars empty along Avenida Revolución, swarms of vendors, pushing awning-topped carts, assemble Tostilocos on the fly for drink-addled customers.

And on Sunday afternoons, when cars line up at San Ysidro to cross from Mexico to the United States, vendors weave between stalled traffic lanes, doling out Tostilocos and aguas frescas to families with children, who reach through car windows with two hands to retrieve their bagged prizes.

At first glance, the dish appears to be a version of Frito Pie, a stunt food mashup built on a base of processed and salted chips and embellished with dissonant toppings.

Yet that view is shortsighted, said Gustavo Arellano, the author of the forthcoming book “Taco USA: How Mexican Food Conquered America.” Tostilocos are better understood as a product of Mexican cultural and culinary reclamation efforts.

The story began when Texas-based Frito-Lay introduced Tostitos in the late 1970s, after Fritos and Doritos had already made their debuts. “Americans wanted authentic Mexican flavors, so that’s what Frito-Lay sold them,” Mr. Arellano said.

“A generation later, Mexicans are now claiming Tostitos for Mexicans by adding a bunch of stuff on top,” he said. “That’s what people in Mexico do with anything that comes down from somewhere else. We change it, we add more ingredients, more toppings.”

He offered two more examples: baroque Mexican sandwiches called tortas cubanas, stacked high with sliced ham, split and griddled hot dogs and avocado slices; and Mexican drinks called micheladas, made from lager beers and flavored with chile pepper, lime and tomato juice.

Chips are not the only vehicles for loco-style treatment. The suffix can describe a number of dishes in the Mexican repertory, including papas locos, which translate as fries topped with shaved rings of onion, Cheddar cheese, chorizo and even bacon bits.

Now American companies are in the game. On the Mexican side, Sabritas, which like Frito-Lay is a unit of PepsiCo, sells shrink-wrapped flats of three-ounce Tostitos bags, emblazoned with serving suggestions for Tostilocos and all manner of variants, including peanut-topped Tostitos, which translate as Tosti-Huate, as well as Tosti-Caprese, capped with tomato and mozzarella slices and basil leaves.

Sabritas promotes these offerings through efforts that recall Coca-Cola’s mid-20th-century plan to repaint corner stores and groceries, as long as the job included a prominent Coca-Cola logo. Today in Mexican border towns, newly painted bodegas (flanked by murals of Tostitos bags bulging with cucumbers, jicama and tamarind candies) advertise themselves as Tosticentros.

On the American side, Tostilocos are sold at candy stores, bodegas and flea markets (often called swap meets) in San Diego and Los Angeles and, farther east, in Phoenix and Houston.

The primary American market for loco variants is Mexican immigrants. But that may change soon. In 2010 Taco Bell embraced the locos coinage when it introduced Doritos Locos Tacos, taco shells made from the same mix of masa and spices used by Frito-Lay to make nacho cheese-flavored Doritos. According to a report in Nation’s Restaurant News, Doritos Locos will be a significant part of the chain’s growth plans for 2012.

Chris Kuechenmeister, a spokesman for Frito-Lay, said the company has also begun to roll out a few Tostilocos sample carts, similar to the ones used in Tijuana movie theaters, at festivals and openings of convenience stores.

Meanwhile, a number of Anglo and Mexican-American restaurateurs have introduced Tostilocos-inspired dishes.

At Barrio Queen in Scottsdale, Ariz., the chef, Silvana Salcido Esparza, who first noticed Tostilocos 10 years ago at a wrestling match in Tijuana, serves a Lucha Libre version, topped with all the customary ingredients, as well as mango. She also serves Mexican-style fries, topped with corn kernels, butter, mayonnaise and cheese, in a version that could be called papas locos.

In San Diego, Jay Porter, the owner of El Take It Easy, a restaurant emphasizing “Mexican wine-country cuisine,” dishes pork belly tacos, rabbit soup with oyster mushrooms and a gentrified take on Tostilocos that incorporates house-fried tortilla chips, house-made persimmon pickles, roasted peanuts and minced pigs’ ears.

“We cook borderlands foods,” said Mr. Porter, a frequent visitor to Tijuana and to Ensenada, farther south. “This place is neither Mexican nor American. It has a culture all its own, and we serve the food of this place.”

While Mr. Porter takes his restaurant work seriously, he does not take Tostilocos seriously. “It’s topped chips,” he said. “That’s better than chips alone. But it’s still chips topped with stuff.”

Back in Tijuana, Berny Bermudez operates the window at Don Rey, his family’s open-air snack stand, set on a bluff above the beach at Playas de Tijuana.

One recent afternoon, as a construction crew worked nearby to extend the fence between Mexico and the United States, he assembled Tostilocos and their variants. To make Tostilocos, Mr. Bermudez opened bags, scooped toppings and squeezed limes. Coco locos, built on bases of coconut meat strips, required more handwork.

He hacked open a coconut, flicked shell shrapnel off his forearm and extracted the juice. He scalped white meat from the cavity, which he arranged in a foam bowl. He chopped cucumbers and jicamas into a rough dice. He added peanuts, nubs of tamarind, a splash of hot sauce and a glug of chamoy. He tossed in loops of pickled pig skins. In the tilted afternoon sun, they looked like the wet ghosts of fried pork rinds past.

As he talked about his grandfather, who once ran a seafood restaurant here, Mr. Bermudez poured a stream of Clamato, a processed clam juice, into the bowl of coconut meat and toppings.

“I’ve seen the stuff on television,” he said, referring to advertisements that Sabritas shows on Mexican stations. “They get how to sell Tostitos, but they don’t understand Tostilocos.”

“This isn’t their food,” he continued. “It’s our food.”