In a large bowl, combine sour cream, milk, chives, salt and pepper. Add potatoes and mix thoroughly. Spread in a 15-in. x 10-in. x 1-in. baking pan. Combine cheese and cornflakes; sprinkle over potatoes. Bake at 350° for 50-60 minutes or until potatoes are tender. Sprinkle with additional chives if desired. Yield: 6-8 servings.