Bake potatoes in a 400 degree oven for about 45 minutes. Test doneness by piercing with a fork or sharp knife. (Alternatively, cook potatoes in the microwave - scrub clean and pierce each potato a couple of times with a fork. Microwave on high for 10-11 minutes)Use a dish towel to handle potatoes, slice in half and scoop the flesh out into a stand mixer (or large bowl).Salt the potatoes and stir with the whisk attachment to break up large pieces and evenly salt potatoes.Add milk, sour cream, butter, garlic powder, bacon (reserve a tablespoon for topping), green onions(reserve a tablespoon of greens for topping) and 1¼ cup of cheddar cheese. Stir with whisk attachment for 30 seconds just to combine ingredients. Do not over mix or potatoes will become starchy, like glue.Spoon mixture into an 8" or 9" baking dish. Top with remaining cheddar cheese, potato chips, and reserved bacon and chives.Bake in preheated 400 degree oven for about 10 minutes or until cheese is completely melted and potatoes are heated through. Turn the broiler to high and broil the top for about 2-3 minutes to brown the potato chip. Watch closely as they can burn quickly.Serve immediately.