01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish.
02 - Heat olive oil in a large skillet over medium heat. Add onion and red bell pepper; sauté for 3–4 minutes until softened. Add garlic and cook for 30 seconds until fragrant.
03 - Add ground beef; cook, breaking up with a spoon, until browned and cooked through, about 6–7 minutes. Drain excess fat if necessary.
04 - Stir in black beans, chili powder, cumin, smoked paprika, oregano, cayenne, salt, and black pepper. Cook for 1–2 minutes to blend flavors.
05 - Pour in 1 cup enchilada sauce and simmer for 2 minutes. Remove from heat.
06 - Spread 1/4 cup enchilada sauce in the bottom of the prepared baking dish. Layer 5 tortillas over the sauce. Spoon half of the beef mixture over the tortillas. Sprinkle with 1 cup cheddar and 1/2 cup Monterey Jack cheese. Repeat with remaining tortillas, beef mixture, and cheeses. Pour remaining enchilada sauce evenly over the top.
07 - Cover with foil and bake for 20 minutes. Remove foil; bake an additional 10–15 minutes until cheese is melted and bubbly.
08 - Let rest for 5–10 minutes before slicing. Garnish with cilantro, scallions, and sour cream as desired.