01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - In a large skillet over medium heat, cook ground beef, breaking up with a spoon, until browned (about 5 minutes). Drain excess fat.
03 - Add diced onion to the beef and cook for 3 minutes, then stir in minced garlic and cook for 1 minute.
04 - Mix in chili powder, cumin, smoked paprika, salt, pepper, corn kernels, and black beans (if using). Cook for 2 more minutes, then remove from heat.
05 - Spread 1/2 cup enchilada sauce on the bottom of the prepared baking dish. Layer 4 tortillas over the sauce, overlapping as necessary.
06 - Spoon half of the beef mixture over the tortillas. Top with 1/3 of the shredded cheeses. Pour 1/2 cup enchilada sauce over the beef layer.
07 - Place the remaining four tortillas on top. Spread the rest of the beef mixture over them, followed by another 1/3 of the cheeses.
08 - Pour the remaining enchilada sauce over the casserole and top with the remaining cheese. Cover with foil and bake for 25 minutes. Remove foil and bake an additional 10 minutes until cheese is bubbly and slightly golden.
09 - Let rest 10 minutes before slicing. Garnish with cilantro, tomatoes, jalapeños, and sour cream as desired.