Preheat oven to 350 F. Grease 9×13 casserole dish and set aside. Place potatoes in a large pot and fill with water to cover. Boil potatoes over medium-high heat for 15 minutes or until tender. Drain.

Add potatoes, evaporated milk, sour cream, and salt and pepper to a large mixing bowl and mash the potatoes slightly, making sure to leave some nice chunks.

Stir in 1 1/2 cups cheese and half of the bacon. Pour into prepared casserole dish.

Bake uncovered for 25 minutes. Top with remaining cheese and bacon and the chives. Bake for an additional 5 minutes or until cheese is melted.