In a large skillet over medium heat, cook ground beef and onion until beef is browned. Drain off any excess fat.
Stir in tomatoes with green chiles, black beans, corn, and green chiles. Add taco seasoning mix and stir until combined.
Spread mixture into a 9x13 inch baking dish. Sprinkle cheese over top.
Bake in preheated oven for 25 minutes. Sprinkle crushed tortilla chips over top and bake an additional 10 minutes, or until cheese is melted and bubbly.
Serve with sour cream if desired.
Interesting Facts
Beef nacho casserole is a great way to use up leftover taco meat.
This casserole can easily be customized to your taste preferences.
This dish can be made ahead of time and refrigerated until ready to bake.