Prick potatoes with a fork and cook in the microwave, 3 or 4 at a time, and scoop out the flesh (while the others are cooking).
In a large saucepan over medium heat, melt butter. Stir in flour and cook about a minute. Whisk in milk, a little at a time, stirring constantly until thickened. Stir in potatoes, salt, pepper, 1/3 cup bacon bits, 2 tablespoons green onions and most of the cheese. Cook until thoroughly heated. Stir in sour cream and heat through. Serve topped with remaining bacon, onions and cheese.
