Cut baked potatoes into 1 inch cubes. Place half in a greased 13 inch x 9 inch x 2 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, at 350 degrees for 20 minutes or until cheese is melted. Sprinkle with onions.