01 - Preheat oven to 375°F. Lightly grease a 9x13-inch casserole dish with cooking spray or oil.
02 - In a large skillet over medium heat, sauté the diced onion, red bell pepper, and minced garlic for 3 to 4 minutes until softened and fragrant.
03 - Add the shredded chicken, drained black beans, cooked rice, chili powder, cumin, salt, and black pepper to the skillet. Stir thoroughly to combine and heat through for 2 to 3 minutes.
04 - Spread a thin, even layer of salsa across the bottom of the prepared casserole dish.
05 - Arrange 3 tortillas over the salsa base, tearing as needed to fully cover the surface.
06 - Spoon half of the chicken and bean mixture evenly over the tortillas. Drizzle with half of the enchilada sauce and half of the remaining salsa. Top with 1 cup of shredded cheese.
07 - Repeat the layering with the remaining 3 tortillas, the rest of the chicken mixture, the remaining enchilada sauce, the remaining salsa, and the final 1 cup of shredded cheese.
08 - Cover the casserole dish tightly with aluminum foil and bake for 20 minutes.
09 - Remove the foil and continue baking for an additional 10 minutes until the cheese is bubbly and lightly golden on top.
10 - Remove from the oven and let the casserole rest for 5 minutes. Dollop with sour cream and sprinkle with fresh cilantro before serving.