1. Preheat the oven to 375°F and lightly grease a 9×13-inch baking dish with nonstick cooking spray.

2. Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 to 4 minutes until softened. Add the ground beef and cook until browned, breaking it apart as it cooks. Drain excess grease if needed.

3. Stir in the garlic and cook for 30 seconds. Add the taco seasoning and water, then mix well. Stir in the black beans, diced tomatoes with green chilies, salt, and black pepper. Simmer for 3 to 5 minutes.

4. Spread a thin layer of salsa in the bottom of the prepared baking dish. Add a layer of tortillas, trimming or overlapping as needed.

5. Spoon part of the beef mixture over the tortillas. Add small spoonfuls of sour cream, spread a little salsa over the top, and sprinkle with some of the Mexican cheese blend and cheddar.

6. Repeat the layers until all ingredients are used, finishing with tortillas, the remaining salsa, and the rest of the cheese on top.

7. Cover loosely with foil and bake for 20 minutes. Remove the foil and bake for another 10 to 15 minutes, until the cheese is melted and bubbly.

8. Let the casserole rest for 10 minutes before slicing. Top with chopped cilantro and serve warm.