Preheat oven to 400 degrees.
Rub potatoes with olive oil and salt and place on baking sheet.
Bake for 45-60 minutes or until tender when pierced with a fork, flipping halfway through.
Let cool for 15 minutes.
Preheat oven to 350 degrees.
Cut potatoes into bite-sized pieces and place in a bowl. Its perfectly acceptable for the potato pieces to slightly fall apart.
Stir in mayonnaise and sour cream.
Set aside 1/3 cup cheese, 3 tbsp bacon, 2 tbsp sliced green onions for the top of the casserole. Stir in remaining ingredients.
Spoon into a greased deep dish 9x9 baking dish or a 9x13 baking dish. Top with reserved shredded cheese and bacon.
Cover dish with foil and bake for 30 minutes, removing foil for the last 10 minutes.
Top with remaining sliced green onions and serve.