In a skillet over medium heat, cook the ground beef until browned, about 5 minutes.

Add chopped onion and minced garlic, cooking until onion is translucent, about 3 minutes.

Stir in black beans, corn, 1/2 cup of enchilada sauce, cumin, chili powder, salt, and pepper. Cook for another 5 minutes.

Preheat the oven to 350°F (175°C).

In a casserole dish, spread a thin layer of enchilada sauce on the bottom.

Layer half of the tortilla quarters over the sauce, followed by half of the beef filling and half of the cheese.

Repeat the layers with the remaining tortillas, beef filling, and cheese.

Pour the remaining enchilada sauce over the top layer and sprinkle with any leftover cheese.

Cover the casserole dish with foil and bake for 20 minutes.

Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.

Let it cool for 5 minutes before serving. Top with sour cream if desired.