In a large pot, boil thinly sliced potatoes in salted water for 8 to 10 minutes until potatoes are tender. Drain and set aside.
In a large pot, melt butter over medium heat. Add flour and cook for 1 minute. Add half and half, garlic powder, salt and pepper. Cook until sauce comes to a low boil. Remove from heat and stir in sour cream. Then stir in the 1/2 cup cheddar cheese.
Preheat oven to 350 degrees F.
Spray a 9x13 baking dish with vegetable spray.
Place 1/3 of the potatoes on the bottom of baking dish.
Spoon 1/3 of the sauce over potatoes.
Next sprinkle 1/3 of the 2 cups of the cheddar cheese over the sauce.
Next sprinkle 1/3 of the bacon over the cheese.
Next sprinkle 1/3 of the chives over the bacon.
Repeat this process 2 more times.
Cover with foil and bake at 350 degrees F for 45 to 50 minutes. Remove foil and return to the oven for 5 more minutes.
Remove from oven and serve