Preheat oven to 350 degrees F. Peel potatoes, and cut into 1 inch chunks.
Place in a large saucepan, (remove comma) and add enough cold water to cover by about 2 inches. Bring to a boil over medium-high heat, then reduce to a simmer. Cook until tender, about 20 minutes.
Drain potatoes, return to pan, cover, and set aside.
Meanwhile, heat a large skillet over medium heat.
Add bacon, and cook until crisp and browned, turning once.
Transfer to paper towels to drain; let cool, and crumble into pieces.
Using a fork, mash the potatoes in pan until light and fluffy.
Add the cream cheese, butter, and sour cream, and stir until combined and smooth.
Add the chives, 2 cups cheddar cheese, half the bacon, salt, and pepper. Stir until well combined.
Transfer to a buttered 3 quart baking dish. Top with remaining 1/2 cup cheddar cheese.
Bake until top is slightly golden and potatoes are heated through, about 30 minutes.
