Place pork chops into a slow cooker; sprinkle with salt and pepper. Layer 1/4 of the sliced potatoes over the pork chops, followed by 1/4 of the onion slices. Sprinkle the onion with 1 tablespoon flour and season with salt and pepper. Repeat the layers of potatoes, onions, 1 tablespoon of flour, and a sprinkle of salt and pepper three more times.
Mix the cheese sauce with milk until smooth and pour over the potatoes. Set the slow cooker to High and cook for 6 hours.