Lightly grease the inside of the slow cooker with nonstick spray or butter.
In a bowl, mix together the cream of chicken soup and sour cream until smooth. Stir in salt and pepper if using.
Layer half of the sliced potatoes evenly in the bottom of the slow cooker.
Spread half of the creamy mixture over the potatoes and sprinkle with half of the shredded cheese.
Repeat the layers with the remaining potatoes, sauce, and cheese.
Cover and cook on LOW for 5–6 hours or HIGH for 3–4 hours until potatoes are tender and sauce is bubbly.
Let rest on WARM for 10–15 minutes before serving to allow the sauce to thicken.
Notes
For a vegetarian version, use cream of mushroom soup. Add garlic powder, onion powder, or cooked bacon for extra flavor. Let rest before serving to thicken sauce.