Creating this Chicken Enchilada Rice Casserole is straightforward. Follow these easy steps for a delightful result:

1. Preheat your oven to 350°F (175°C).
2. Combine Ingredients: In a large mixing bowl, combine the cooked rice, shredded chicken, black beans, corn, salsa, and ½ cup of the enchilada sauce. Mix well.
3. Season the Mixture: Add the chili powder, cumin, salt, and pepper to the mixture. Stir to ensure even distribution of the seasoning.
4. Layer the Casserole: In a greased 9×13-inch baking dish, spread half of the rice and chicken mixture evenly on the bottom.
5. Add Sauce and Cheese: Pour half of the remaining enchilada sauce over the mixture. Sprinkle half of the cheddar and Monterey Jack cheese on top.
6. Repeat Layers: Add the remaining mixture on top, followed by the rest of the enchilada sauce and cheese. Ensure everything is well covered.
7. Bake: Place the baking dish in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbly and has turned golden.
8. Garnish: Once baked, remove the casserole from the oven and let it cool slightly before garnishing with chopped green onions.
9. Serve: Dish out generous portions onto plates, ensuring each serving has ample cheese and sauce.

These steps will guide you through the preparation, making it easy to create this amazing casserole.