In a medium bowl, stir together 1 1/2 cups of the mozzarella cheese, mashed potatoes, sour cream, salt, pepper, and garlic powder until evenly blended.
Spread the potato mixture into a 9x13 inch baking dish.
Sprinkle bacon and the remaining 1 1/2 cups of mozzarella cheese over the top.
Top with crushed potato chips.
Bake in preheated oven for 20 minutes, or until cheese is melted and bubbly.
Interesting Facts
The potato chip casserole is a great way to use up leftover mashed potatoes.
This dish can be served as a main course or a side dish.
The casserole can be made ahead of time and stored in the refrigerator for up to two days.