Preheat the oven to 375° F and spray cooking spray lightly in a 9 x 13 casserole dish.
Brown the ground beef in a skillet over medium heat and sauté the onions at the same time.
Drain the fat from the ground beef and onion mixture.
Next add in and thoroughly mix up the taco seasoning, garlic, Rotel, corn, and black beans
In a large mixing bowl add the tater tots, 3/4 of the shredded cheese, and the mixture of the skillet and toss all together until well combined.
Pour 1/3 of the enchilada sauce in the bottom of the prepared casserole dish and spread it out.
Dump the tater tot mixture into the dish and press down evenly into the casserole dish. Then top it all with the remaining enchilada sauce.
Bake in the oven at 375° F for 40 minutes. Sprinkle the rest of the shredded cheese over top of the casserole and bake another 5 minutes for the cheese to melt.
Serve it up and enjoy. You can add your favorite toppings: sliced black olives, guacamole, sour cream, salsa, and more.