Preheat the oven to 375°F.
In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until softened. Stir in the minced garlic and cook for another minute.
Add the ground beef or turkey to the skillet. Cook until browned and fully cooked, breaking it apart with a spoon. Drain any excess fat.
Stir in the chili powder, cumin, paprika, salt, and pepper. Add the black beans, corn, and diced tomatoes. Mix well and let it simmer for 5 minutes.
In a greased 9x13-inch baking dish, spread a layer of the meat mixture on the bottom. Place a layer of tortilla quarters over the meat, followed by a layer of shredded cheese. Repeat the layers until all ingredients are used, finishing with a layer of cheese on top.
Cover the dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden.
Let the casserole cool for 5-10 minutes before serving. Top with sour cream and fresh cilantro if desired.