Set oven to 450ºF. Mist muffin pan cups with cooking spray.
For mini-sized muffin pan: Place 2-3 tots in each muffin cup. For regular sized muffin pan: Place 4-5 tots in each muffin cup.
Position muffin pan on bottom rack of the oven and bake 10 minutes. Take the pan out of the oven.
Coat bottom of shot glass or small juice glass with cooking spray. Keep a small gap between the glass and cupcake pan opening. Rotate the glass or container until the edges of the potatoes are close to the top of the muffin tin opening to create a potato cup. See video below for a demonstration. Put back in oven; bake additional 15 minutes or until deep golden brown.
Add 1 tablespoon of cheese to each potato cup. Bake for 4-5 minutes, or until the cheese has melted. Move to platter and let cool for 5 minutes.
Top and finish the loaded tater tot appetizer cups with sour cream, bacon, and green onions. Serve warm.