01 -
Heat your oven to 350°F. Spray a 9x13 inch baking dish with cooking spray and set it aside.
02 -
Brown the ground beef and diced onion in a large skillet over medium heat. Cook until the meat is no longer pink and the onions are soft.
03 -
Stir in the minced garlic and cook for another minute until fragrant. Add taco seasoning and water, stirring until everything is well mixed. Add the diced tomatoes with their juices, green chiles, and drained black beans. Stir everything together and let it heat through.
04 -
Arrange 6 corn tortillas in the bottom of your prepared baking dish, overlapping them slightly to cover the entire bottom. Spread one-third of the meat mixture over the tortillas, then sprinkle 2 cups of cheese on top. Repeat this process two more times for three complete layers.
05 -
Cover tightly with aluminum foil and bake for 30-40 minutes until the casserole is bubbling and the cheese is completely melted.
06 -
Let the lasagna sit for 10 minutes before cutting. Top with diced tomatoes and green onions, and serve with sour cream.