Hillen and Mueller scored 1:37 apart against Carolina backup goalkeeper Justin Peters, who entered the game at the start of the third.
Carolina goalkeeper Cam Ward saw his first action of the preseason after being slowed by upper body stiffness since the opening of training camp a week ago. Ward started and played 40 minutes. He gave up a goal to Nashville's David Legwand at 17:58 of the second period.
Anders Lindback came off the bench in goal for the Predators and played the final two periods. He stopped 20 of 21 shots to get the win.
Nashville won for the third time in four preseason games, while Carolina dropped its second straight decision.