Preheat oven to 375 degrees and spray a 9×13 baking dish with cooking spray. For extra crispy tater tots, bake tater tots for about 10 minutes while preparing the beef mixture – otherwise prepare as follows.
In a large skillet, brown the beef and the onion. Add the garlic towards the end of the browning process and cook for 1 minute. Drain.
Add the green chiles, taco seasoning mix, black beans, corn, and 2 cups of the cheese. Stir together to combine. If your skillet isn’t big enough you may need to stir it together in a bowl.
Pour mixture into the prepared 9×13 pan. Arrange tater tots on top of the mixture in a single layer.
Pour the enchilada sauce on top of the casserole as evenly as you can.
Bake uncovered for 30-40 minutes or until tater tots are nice and crispy. Sprinkle the remaining 1 cup of cheese on top and place back in the oven for 2-3 minutes or until cheese has melted.
Top with olives, cilantro, sour cream, tomatoes when serving if desired.