Follow these simple steps to create your Chicken Enchilada Rice Casserole:

1. Preheat your oven to 350°F (175°C).
2. In a large bowl, combine the cooked rice, shredded chicken, enchilada sauce, black beans, corn, cumin, chili powder, garlic powder, onion powder, salt, and pepper. Mix well until all ingredients are combined.
3. Spread half of the mixture evenly in a greased 9×13-inch baking dish.
4. Sprinkle half of the shredded cheese over the first layer.
5. Layer the remaining rice mixture on top of the cheese.
6. Top with the remaining cheese, ensuring an even spread.
7. Cover with aluminum foil and bake for 20-25 minutes.
8. Remove foil and bake for another 10-15 minutes, or until cheese is bubbly and lightly golden.
9. Let it cool for about 5-10 minutes before serving to allow the casserole to set.
10. Garnish with fresh cilantro and serve with sour cream if desired.

These straightforward instructions will help you create a flavorful Chicken Enchilada Rice Casserole without any hassle.