In a medium bowl, mix the sour cream, cream cheese, and mashed potatoes until smooth.
Add ¾ cup of the cheddar cheese, most of the bacon bits, and most of the green onions, onion salt, and garlic powder to the potatoes. Mix well.
Pour into a small casserole dish, coated with non-stick cooking spray, and top with the remaining cheese. Bake for 30 minutes or until the cheese is melted and bubbly around the edges.
Top with the remaining bacon and green onions. Serve with your favorite dippers.