Place potato nuggets in a large microwave-safe bowl. Heat in the microwave until thawed, 1 to 2 minutes. Add butter and salt; mash together until potato nuggets are crumbled. Press evenly into a glass pie dish to make crust.
Bake crust in the preheated oven until golden brown, 20 to 25 minutes.
Reduce oven temperature to 350 degrees F (175 degrees C).
Combine Cheddar cheese, ham, Parmesan cheese, and flour in a bowl.
Beat 4 eggs in a bowl until smooth. Add milk, onion, green bell pepper, salt, onion powder, and garlic powder. Stir into Cheddar cheese mixture until combined. Pour over crust.
Bake in the preheated oven until set and golden, about 45 minutes. Let cool before slicing, 10 to 15 minutes.