In a skillet, cook the ground beef over medium heat until browned. Drain any excess fat.
Add the chopped onion and minced garlic to the skillet. Cook until the onion is translucent.
Stir in the black beans, chili powder, cumin, salt, and black pepper. Cook for another 2-3 minutes.
Spread a thin layer of enchilada sauce on the bottom of a baking dish.
Place a layer of tortillas over the sauce, then add a layer of the beef and bean mixture, followed by a layer of shredded cheese. Repeat the layers until all ingredients are used, ending with a layer of cheese on top.
Bake in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbly.
Let the casserole cool for a few minutes before serving.
Notes:
You can add some chopped cilantro or green onions on top for extra flavor.