Preheat the oven to 350F. Peel the potatoes and cube into 2-inch pieces.
Place the cubed potatoes in a large pot or dutch oven. Pour water over the potatoes so that they are completely covered. Add 1 teaspoon of the salt to the water.
Bring the potatoes to a boil. Reduce the heat and let simmer for 20 minutes, until the potatoes are fork tender. Drain the water, and return the potatoes to the pot.
Mash the potatoes until relatively smooth. A few lumps are okay.
Add the sour cream, butter, ground black pepper, and remaining 1 teaspoon of salt to the potatoes. Stir until the butter is melted and everything is evenly distributed.
Add the chives, half of the bacon and cheese, reserving the rest for later. Mix until combined.
Spoon the mashed potatoes into a greased 9x13-inch casserole dish.
Top with remaining bacon and cheese.
Bake at 350F for 20-30 minutes, until the cheese is melted on top. Serve warm with additional fresh chives if desired.