Preheat oven to 450°F
Poke potatoes with a fork 3-4 times. Coat potatoes with oil and transfer to a rimmed baking sheet. Bake for 30 minutes. Brush potatoes with more oil and sprinkle with salt. Bake 15-20 more minutes or until potatoes are cooked through and tender. Remove from oven and let cool enough to handle.
Heat oven to 350°F
Slice potatoes lengthwise. Score the inside and carefully scoop out while keeping skins intact. Discard the skins from 2 potatoes. Place prepared skins on rimmed baking sheet.
Combine potato filling, sour cream, shredded cheese, salt, pepper and garlic powder.
Whip with hand mixer. Add milk 1 Tb at a time until mixture becomes creamy.
Fill potato skins with mixture and top with additional shredded cheese.
Bake for 15 minutes. Broil on high 2-3 minutes to brown.
Top with fresh chives and serve immediately.