Nernberger competed in three Junior National Championships, with his best finish at fourth place in 2002 and 2004. He has medaled at the Men's National Championship three times, all in a row on skip Craig Brown's team, silver in 2014 and 2015 and bronze in 2016. Later in 2016 Nernberger was invited to be alternate on the US Champion team, skipped by John Shuster, as they represented the United States at the World Championship. There they won the bronze medal, defeating Japan's Yusuke Morozumi in the bronze medal match.