Nemmers is notable for officiating in Super Bowl XXV, as well as several playoff games. Beginning his seventeenth season as referee with the 2007 NFL season, Nemmers' officiating crew consists of Undrey Wash, Mark Baltz, Mike Spanier, Mike Weir, Carl Cheffers, and Dino Paganelli. The 2007 season will also be the final year for Nemmers as he as announced his retirement.