Preheat the oven to 400 degrees F (200 degrees C).

Heat oil in a 9-inch cast iron skillet over medium heat. Add chorizo; cook, stirring to crumble, until browned and cooked through, about 5 minutes. Transfer to paper towels to drain. Drain any excess fat from the skillet.

Without cleaning the skillet, add bell peppers and onion. Cook over medium-high heat, stirring often, until browned and softened, about 5 minutes. Remove skillet from heat and stir in tequila. Continue cooking vegetables, stirring often, until golden brown, about 3 minutes. Using a slotted spoon, transfer vegetables to a bowl.

Stir together Monterey Jack and Cheddar cheeses in a bowl; spread 1/3 in the skillet. Add 1/3 of the vegetables, then 1/3 of the chorizo. Repeat with 2 more layers, ending with chorizo. Sprinkle with chili powder.

Bake in the preheated oven until cheeses are melted and bubbling, about 8 minutes. Remove from the oven and top with tomatoes, cilantro, and salt. Serve immediately.