Trim ends of potatoes. Slice potatoes into 1-in.-thick rounds. Brush with butter; sprinkle with salt and pepper. Place potatoes on grill rack, buttered side down. Grill, covered, over medium heat or broil 4 in. from heat until browned, 5-7 minutes. Brush with remaining butter; turn. Grill or broil until browned, 5-7 minutes longer., Top with sour cream, cheese, bacon and chives.