Place the potatoes in a large pot with water to cover over high heat. Bring to a boil and cook until the potatoes are tender. Remove from heat, drain, then combine with the milk and 6 tablespoons of butter, mash and set aside.
Melt the remaining 2 tablespoons of the butter in a large skillet over medium high heat. Saute the bacon, onion and garlic in the butter for 5 to 10 minutes, or until the bacon is fully cooked.
Cook the lasagna noodles according to package directions and cool under running water.
Place 1/2 of the mashed potatoes into the bottom of a 9x13 inch baking dish. Top this with 1/3 of the cheese, followed by a layer of lasagna noodles. Repeat this with the remaining potatoes, another 1/3 of the cheese and a layer of noodles. Then arrange the bacon, onion and garlic over the noodles, then another layer of noodles, and finally top all with the remaining cheese. Season with salt and pepper to taste.
Bake, uncovered, at 350 degrees F (175 degrees C) for 30 to 45 minutes, or until the cheese is melted and bubbly. Serve with sour cream and chopped fresh chives.