Preheat the oven to 375 degrees F (190 degrees C). Prepare a 9x13-inch baking dish with cooking spray.
Cook ground beef in a skillet over medium heat until completely browned, 5 to 7 minutes. Add in frozen corn, black beans, onion, garlic, and taco seasoning mix to ground beef; cook and stir another 10 minutes. Set aside to cool slightly.
Combine ground beef mixture in a large bowl with about 3/4 of the Mexican cheese blend and the potato nuggets; stir to combine.
Pour about 1/3 of the enchilada sauce into the bottom of the prepared baking dish. Add the tater tot mixture to the baking dish; lightly pat the mixture down into a solid, even layer. Pour remaining enchilada sauce over the potatoes.
Bake in the preheated oven for 40 minutes. Sprinkle remaining cheese over the casserole and return to the oven until the cheese is melted and bubbly, about 5 minutes more.
