1. Preheat the oven to 425°F and lightly grease a sheet pan or line it with parchment paper.

2. Heat the olive oil in a large skillet over medium heat and cook the ground beef until it starts to brown.

3. Add the onion and bell pepper, then cook until softened and the beef is fully cooked.

4. Stir in the garlic and taco seasoning and cook for 30 seconds until fragrant.

5. Add the diced tomatoes with green chiles, black beans, and corn, then cook for 3 to 4 minutes until the mixture is heated through and not too wet.

6. Arrange tortillas around the sheet pan so they cover the bottom and hang slightly over the edges, adding extra tortillas in the center if needed.

7. Sprinkle half of the shredded cheese over the tortilla base.

8. Spread the beef mixture evenly over the cheese layer.

9. Top with the remaining cheese.

10. Add more tortillas over the filling, then fold the overhanging tortillas toward the center to enclose everything.

11. Brush the top with melted butter or oil.

12. Bake for 20 to 25 minutes until golden brown and crisp.

13. Let rest for 5 to 10 minutes, then slice and serve.