01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with cooking oil or butter.
02 - Heat a large skillet over medium heat with a splash of oil. Add diced onion and bell pepper, sautéing for 4-5 minutes until softened. Stir in minced garlic and cook for 1 additional minute.
03 - Add corn, black beans, shredded chicken, ground cumin, chili powder, smoked paprika, salt, and black pepper to the skillet. Cook for 2-3 minutes, stirring occasionally until heated through. Remove from heat.
04 - Spread 1/2 cup enchilada sauce evenly across the bottom of the prepared baking dish.
05 - Arrange 1/3 of the tortillas over the sauce, overlapping them slightly to cover the entire surface.
06 - Distribute half of the chicken-bean mixture over the tortillas. Pour 1/2 cup enchilada sauce evenly over the filling. Sprinkle 2/3 cup shredded cheese across the top.
07 - Layer another 1/3 of the tortillas. Add the remaining chicken-bean mixture, 1/2 cup enchilada sauce, and 2/3 cup cheese.
08 - Top with the final 1/3 of tortillas. Pour remaining enchilada sauce over the top and distribute the remaining cheese evenly.
09 - Cover the baking dish with aluminum foil. Bake for 25 minutes.
10 - Remove foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden brown.
11 - Allow the casserole to rest for 10 minutes before serving. Top with sour cream and desired garnishes including fresh cilantro, jalapeños, avocado, or lime wedges.