Preheat oven to 425°F. Spray two 24 mini muffin pans with oil.
Put 3 tater tots in each of 48 mini muffin cups. Bake for 10 minutes. Leave the oven on. Using the bottom of a small shot glass or the end of a wooden spoon, smash the tots down to form cups; do not break through the potatoes. Bake for another 15 minutes or until golden brown and crispy.
Combine cream cheese, Mexican cheese, Hatch chiles, and onion powder until well mixed. Divide the mixture between the 48 tater cups. Return to the oven for 10 minutes or until the cheeses are melted and lightly golden brown on top.