Preheat oven to 350F. Cut baked potatoes into 1 inch cubes. Place half in a greased 13x9 inch baking dish. Sprinkle with half of the salt, pepper, and bacon. Top with half of the sour cream and cheeses. Repeat layers.
Bake, uncovered 20-25 minutes or until cheeses are melted. Sprinkle with onions.