Preheat the oven to 350°F (175°C).

In a skillet, cook the ground beef with the chopped onion over medium heat until browned.

Drain excess fat, then stir in the canned tomatoes, black beans, and taco seasoning.

In a large baking dish, layer half of the crushed tortilla chips at the bottom.

Spread half of the beef mixture over the chips, followed by half of the shredded cheese.

Repeat the process with the remaining chips, beef mixture, and cheese, finishing with a top layer of cheese.

Cover the dish with foil and bake for 20 minutes.

Remove the foil and bake for an additional 10-15 minutes until cheese is bubbling and golden.

Let the casserole cool for 5-10 minutes before serving.

Serve with sour cream and fresh cilantro on top.