Preheat your oven to 350°F. Lightly spray a 9x13-inch casserole dish with non-stick cooking spray and set it aside.

In a large skillet over medium heat, cook the ground beef and diced onion until the meat is browned and the onion is softened. Add the minced garlic and sauté for 1-2 more minutes.

Stir in the taco seasoning and water, mixing well, and let it simmer over medium heat. Add the fire-roasted diced tomatoes (with their juices), green chiles, and black beans. Stir to combine and heat through.

In the prepared casserole dish, layer 6 corn tortillas on the bottom, overlapping them slightly. Spread 1/3 of the meat mixture over the tortillas, then sprinkle 2 cups of cheese on top.

Repeat the layering process, using more tortillas, meat mixture, and cheese for a total of three layers.

Cover the casserole with aluminum foil and bake for 30-40 minutes, or until it’s bubbly and the cheese is melted.

Once baked, garnish with diced tomatoes and sliced green onions. Let the casserole rest for 10 minutes before slicing and serving.

Serve with a dollop of sour cream for extra flavor.