01 - Preheat oven to 375°F. Lightly grease a 9x13-inch casserole dish with nonstick spray or butter.
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 pepper to the skillet. Stir thoroughly to combine and cook for 2 to 3 minutes until heated through.
04 - Spread a thin, even layer of salsa across the bottom of the prepared casserole dish. Arrange 3 tortillas over the salsa, tearing them as needed to form an even layer.
05 - Spoon half of the chicken and bean mixture over the tortillas. Drizzle with half of the enchilada sauce and half of the remaining salsa. Sprinkle 1 cup of shredded cheese evenly on top.
06 - Repeat the layering: place the remaining 3 tortillas over the cheese, then spread the rest of the chicken mixture, enchilada sauce, salsa, and the final cup of cheese.
07 - Cover the casserole tightly with aluminum foil and bake for 20 minutes to allow the layers to heat through and meld together.
08 - Remove the foil and continue baking for 10 more minutes until the cheese is bubbly and lightly golden on top.
09 - Remove the casserole from the oven and let it rest for 5 minutes. Top with dollops of sour cream and a sprinkle of fresh cilantro before serving.