PLACE potatoes in large saucepan. Cover with water; bring to a boil. Cook over medium-high heat for 15 to 20 minutes or until tender; drain.
PREHEAT oven to 350° F. Grease 2 1/2- to 3-quart casserole dish.
RETURN potatoes to saucepan; add evaporated milk, sour cream, salt and pepper. Beat with hand-held mixer until smooth. Stir in 1 1/2 cups cheese and half of bacon. Spoon mixture into prepared casserole dish.
BAKE for 20 to 25 minutes or until heated through. Top with remaining 1/2 cup cheese, remaining bacon and green onions. Bake for an additional 3 minutes or until cheese is melted.