01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - Heat olive oil in a large skillet over medium heat. Add onion and cook 2-3 minutes until softened. Add garlic and sauté 30 seconds.
03 - Add ground beef, breaking up with a spoon until browned and cooked through, 5-7 minutes. Drain excess fat if necessary.
04 - Stir in cumin, chili powder, smoked paprika, salt, and pepper. Mix well to combine.
05 - Add black beans and green chilies if using. Cook 2 minutes, then remove from heat.
06 - Spread 1/2 cup enchilada sauce in the bottom of the prepared baking dish.
07 - Layer 4 tortillas over the sauce, overlapping as needed. Top with half the beef mixture, 3/4 cup cheddar cheese, and 1/2 cup Monterey Jack cheese. Drizzle with 1/2 cup enchilada sauce.
08 - Repeat with remaining tortillas, beef mixture, cheeses, and sauce, finishing with both cheeses on top.
09 - Cover with foil and bake 20 minutes. Remove foil and bake 10 minutes more until cheese is bubbly and golden.
10 - Cool 10 minutes before garnishing with cilantro, green onions, and sour cream if desired. Slice and serve.