Bring a large saucepan of lightly salted water to a boil over medium-high heat.
Add the potatoes; cook for 15 to 20 minutes, or until tender when pierced with a fork. Drain and return to the saucepan.
Slightly mash potatoes. Stir in milk, sour cream, salt, pepper, and garlic powder.
Mash until the desired texture is reached. Cook for 5 minutes over low heat, stirring occasionally, until heated through.
Garnish with chives.