Making Tex Mex Casserole is straightforward. Follow these easy steps to create your own savory masterpiece:

1. Preheat Oven: Start by preheating your oven to 350°F (175°C).
2. Cook the Meat: In a large skillet, heat the olive oil over medium heat. Add the chopped onions and sauté until translucent. Then, add the ground beef (or turkey) and cook until browned. Drain any excess fat.
3. Season the Meat: Stir in the taco seasoning, cumin, garlic powder, salt, and pepper. Mix until well combined.
4. Combine Ingredients: In a large bowl, combine the cooked meat mixture with black beans, corn, diced tomatoes, and cooked rice. Mix thoroughly.
5. Layer the Casserole: In a greased 9×13 inch baking dish, start with a layer of the meat mixture. Follow with a layer of crushed tortilla chips, then sprinkle with half the cheddar and Monterey Jack cheese.
6. Repeat Layers: Repeat the layering process with the remaining meat mixture, crushed tortilla chips, and the rest of the cheese.
7. Bake: Place in the preheated oven and bake for about 25-30 minutes, or until the cheese is bubbly and slightly golden.
8. Rest: Remove from the oven and allow the casserole to rest for about 10 minutes before serving.
9. Garnish: Top with fresh cilantro if desired for added freshness and flavor.

These clear and manageable steps ensure your Tex Mex Casserole turns out delightful every time!