Preheat the oven to 375F.
Brown the ground beef in a large skillet with the onions.
2 lb ground beef, 1 medium to large onion
Then, drain any excess grease from the beef mixture.
Next, stir in the taco seasoning and water.
4 tablespoons taco seasoning, 1 cup water
Add the salsa and sour cream; mix well.
1 cup sour cream, 2 cup salsa
Stir in the black beans and corn.
2 15 oz cans black beans, 2 15oz cans corn kernels
Remove from the heat and top with shredded cheese.
3 cups shredded Mexican-blend cheese
Add a layer of corn chips to the top of the casserole.
4 cups Frito corn chips
Cover with aluminum foil.
Bake for 15 minutes until the cheesy is melted and the casserole is bubbly.
Uncover and cook 5 minutes more.