Cook the potatoes in a medium pot of boiling salted water for 5 minutes or until the potatoes are tender. Drain and cool the potatoes. Meanwhile, stir together 1/3 cup sour cream, mayonnaise, mustard, salt, and pepper in a small bowl. Combine the potatoes, half of the bacon, half of the cheese and half of the green onions in a large bowl. Stir with the dressing until coated. Garnish with remaining bacon, cheese and green onions. Top with 1/4 cup sour cream and sprinkle with chives. Store in refrigerator.