Preheat the oven to 350°F. Spray an 13 x 9- inch baking dish with cooking spray and set aside. Use a mandolin to thinly slice potatoes. Add to a large pot and cover with water. Add salt.
Parboil for around 5 minutes or just until fork tender. Drain well.
In a large mixing bowl, mix together both soups, half & half, sour cream, butter, crumbled bacon, buttermilk dressing mix, chives and 1 1/2 cups cheese.
Add drained potatoes to the mixing bowl. Using a large spoon or spatula gently fold the potatoes int the sauce..
Spread the potatoes evenly into the baking dish and sprinkle the remaining cheese on top.
Bake for 35-40 minutes or until golden and bubbly.
Sprinkle the top with chopped chives and allow to rest on the counter for 5-10 minutes before serving.