Prep Time: 40 minutes
Cook Time: 25 minutes
Cook potatoes in boiling water 25 minutes or until fork tender. Drain; return to same pan. Add sour cream and butter. Mash with potato masher or electric mixer. Stir in bacon and 2 tablespoons chives. Add Mozzarella cheese and mix well.
Spoon into greased 3-qt. casserole; top with Swiss cheese. Bake in preheated 350°F oven 25 minutes or until cheese is lightly browned and potatoes are heated through. Sprinkle with remaining chives.