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

2. Spread a thin layer of enchilada sauce over the bottom of the baking dish.

3. Cook the ground beef in a large skillet over medium heat until browned, breaking it into crumbles.

4. Add the diced onion and cook until softened, then stir in the garlic until fragrant.

5. Drain excess grease from the skillet if needed.

6. Stir in the taco seasoning, salsa, black beans, corn, and half of the enchilada sauce.

7. Simmer the beef mixture for 3 to 5 minutes until slightly thickened.

8. In a bowl, mix the softened cream cheese and sour cream until smooth.

9. Place tortillas in the bottom of the baking dish, trimming or overlapping as needed.

10. Add a layer of beef mixture, spoon over some of the cream cheese mixture, and sprinkle with cheddar and Monterey Jack.

11. Repeat the layers until the filling is used, ending with tortillas, remaining enchilada sauce, and shredded cheese on top.

12. Bake uncovered for 25 to 30 minutes, until the cheese is melted, bubbly, and lightly golden.

13. Let the casserole rest for 10 minutes before slicing.

14. Top with diced tomatoes, green onions, cilantro, sour cream, and jalapeños before serving.