01 - Preheat oven to 375°F.
02 - In a large skillet over medium heat, cook the ground beef until browned, breaking it up with a spatula (about 5 minutes). Drain excess fat if needed.
03 - Add the chopped onion and cook until softened, about 3 minutes. Stir in garlic, chili powder, cumin, smoked paprika, oregano, salt, and black pepper; cook for 1 minute until fragrant.
04 - Pour in 1 cup of enchilada sauce and stir to combine. Remove from heat.
05 - Spread 1/4 cup enchilada sauce in the bottom of a 9x13-inch baking dish.
06 - Layer one-third of the tortilla pieces over the sauce. Top with half the beef mixture, then sprinkle with a mix of cheddar and Monterey Jack cheese (about 1/3 of the total cheese).
07 - Add another layer of tortillas, the remaining beef, and another third of the cheese.
08 - Top with final layer of tortillas, remaining enchilada sauce, and the rest of the cheese.
09 - Cover with foil and bake for 20 minutes.
10 - Remove foil and bake an additional 10 minutes, until cheese is bubbly and golden.
11 - Let rest for 10 minutes before slicing. Garnish with cilantro, green onions, and serve with sour cream if desired.