Twice-Baked Potato Casserole

8 medium baking potatoes, baked (about 4 pounds)
2 cups shredded cheddar cheese, divided (8 ounces)
1 (16 ounce) container sour cream
1 (8 ounce) package cream cheese, softened
1/2 cup milk
1/2 cup butter or 1/2 cup margarine, melted
2 garlic cloves, minced
1 tablespoon chopped fresh chives
1 1/2 teaspoons salt
1/2 teaspoon pepper
6 slices bacon, cooked and crumbled
4 green onions, chopped
1/4 cup chopped fresh chives
Directions:

1. Peel potatoes, and coarsely mash pulp with a potato masher. Stir in 1 cup Cheddar cheese and next 8 ingredients. Spoon into a lightly greased 13x9-inch baking dish.
2. Bake a 350 degrees Fahrenheit for 30 minutes or until thoroughly heated. Sprinkle with remaining 1 cup cheese, bacon, green onions, and chives.