Line a slow cooker with aluminum foil, leaving enough to overhang to wrap the potatoes on top, and coat with nonstick spray. Place a layer of potatoes evenly into the slow cooker. Top with cheese, Ranch Seasoning and bacon, repeating 2 more times and reserving ½ cup cheese.

Cover potatoes with aluminum foil and cook on low heat for 7-8 hours or high heat for 3-4 hours. Sprinkle with remaining ½ cup cheese. Cover and cook until melted, about 1-2 minutes.

Serve immediately, garnished with chopped green onion