- To prepare the chicken, in a large fry pan over medium heat, warm the oil until almost smoking. Add the onion and cook, stirring occasionally, until softened, about 5 minutes. Add the garlic and cook until fragrant, about 1 minute. Add the chicken, cumin, chili powder, cayenne, tomatoes, cilantro and oregano and stir to combine. Season with salt. Stir in the stock and cook until most of the liquid has been absorbed and the tomatoes are soft, 5 to 10 minutes. Taste and adjust the seasonings with salt. Set aside.
- Line a baking sheet with paper towels. In a 4-quart saucepan over medium heat, pour in oil to a depth of 3 inches and heat to 360°F on a deep-frying thermometer. Using a tortilla basket according to the manufacturer's instructions, fry the tortillas one at a time until golden brown, 2 to 3 minutes. Transfer to the prepared baking sheet.
- Place each fried tortilla on an individual plate. Top with lettuce, beans, chicken, cheese, tomatoes, cilantro, avocado and salsa, dividing equally. Pass additional salsa alongside.