Place the potatoes into a pan, and fill with just enough water to cover. Bring to a boil, then simmer over low heat until tender, about 10 minutes. Drain, and cool under cold running water.
In a large bowl, stir together the sour cream, mayonnaise, and 1/2 cup of chives. When the potatoes have cooled, stir them into this mixture. Season with salt and pepper. Garnish with remaining chives.