01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish with cooking spray or a small amount of oil.
02 - In a large skillet over medium heat, cook ground beef, breaking up with a spoon, until browned throughout, approximately 5 minutes. Drain excess fat from the skillet.
03 - Add diced onion to the beef and cook for 3 minutes until softened. Stir in minced garlic and cook for 1 minute until fragrant.
04 - Mix in chili powder, cumin, smoked paprika, salt, pepper, corn kernels, and black beans. Cook for 2 minutes to blend flavors, then remove from heat.
05 - Spread 1/2 cup enchilada sauce evenly on the bottom of the prepared baking dish. Arrange 4 tortillas over the sauce, overlapping as necessary to cover the surface.
06 - Spoon half of the beef mixture over the tortillas. Top with 1/3 of the shredded cheese blend. Pour 1/2 cup enchilada sauce over the beef layer.
07 - Place the remaining 4 tortillas on top. Spread the remaining beef mixture over them, followed by another 1/3 of the cheeses. Pour the remaining enchilada sauce over the casserole and top with the remaining cheese.
08 - Cover the baking dish tightly with aluminum foil. Bake for 25 minutes to heat through and blend flavors.
09 - Remove foil and bake an additional 10 minutes until cheese is bubbly and lightly golden on top.
10 - Let the casserole rest for 10 minutes before slicing to allow layers to set. Garnish with cilantro, tomatoes, jalapeños, and sour cream as desired.