Preheat oven to 425°F (218°C). Line two rimmed baking sheets with parchment paper.

Prepare ingredients: slice the chicken sausage; seed and thinly slice the red, orange, and yellow bell peppers; peel and thinly slice the red onion.

In a large bowl combine the sliced sausage, sliced peppers, sliced onion, and 2 tablespoons olive oil; toss to coat evenly.

In a small bowl whisk together 2 teaspoons cornstarch, 2 teaspoons chili powder, 1 teaspoon kosher salt, ½ teaspoon smoked paprika, ½ teaspoon cumin, ½ teaspoon oregano, ½ teaspoon garlic powder, and ¼ teaspoon cayenne pepper (optional).

Sprinkle the spice-cornstarch mixture over the sausage and vegetables and stir/toss until everything is evenly coated.

Divide the mixture evenly between the two prepared sheet pans and spread into a single thin layer.

Bake for about 15 minutes, stirring and flipping the mixture once halfway through (about 7–8 minutes), until the vegetables are tender and the sausage and edges are golden brown.

Optional: for extra browning, place the pans under the broiler for 1–3 minutes, watching closely to avoid burning.

Lightly steam the 12 (6-inch) flour tortillas and keep them warm until serving.

To serve, spoon the chicken sausage and pepper mixture onto the warmed tortillas and top each with a sprinkle of ½ cup minced cilantro and ½ cup crumbled cotija cheese.