Preheat the oven to 350℉. Spray a 9x13-inch pyrex pan with nonstick spray.
Sprinkle the ham evenly into the bottom of the prepared baking pan.
In a medium bowl, whisk together the eggs, milk, onion powder, salt, garlic powder and pepper. Pour the egg mixture over the top. Sprinkle on ½ of the cheese, and then add the Tater Tots evenly on top of the cheese. Cover with foil.
Bake for 40 minutes, Take off the foil, sprinkle the rest of the cheese on top. And then sprinkle on the green onions. Bake for 20 minutes more. Let sit for a few minutes, then serve!