Step 1: Prepare the Base

Preheat your oven to 375°F (190°C). Heat a large skillet over medium-high heat. Add the ground beef and diced onion, cooking until the meat is browned and the onion is softened, about 5–7 minutes. Drain any excess grease.

Step 2: Add the Seasonings and Vegetables

Stir in the taco seasoning, black beans, and diced tomatoes with green chilies. Let the mixture simmer for 3–5 minutes, allowing the flavors to meld together.

Step 3: Layer the Casserole

In a greased 9×13-inch baking dish, spread half of the crushed tortilla chips evenly across the bottom. Layer half of the beef mixture over the chips, followed by a generous sprinkling of shredded cheese. Repeat the layers, finishing with a final layer of cheese on top.

Step 4: Bake the Casserole

Cover the dish with aluminum foil and bake for 15 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.

Step 5: Add Toppings and Serve

Remove the casserole from the oven and let it cool slightly. Top with your choice of fresh toppings like shredded lettuce, diced tomatoes, or sour cream. Serve warm and enjoy!