Fettner contested his first international jumping on December 21, 2002 at the FIS race in Hinterzarten . In the Junior World Championship 2004 in Norway Stryn he won the gold medal with the Austrian team. In 2006 Fettner won the overall ranking in the FIS Cup after several podium finishes . A year later he was able to reach the 51st place in the overall ranking in the Summer Grand Prix 2008 after he reached once the 12th and once the 13th place in a jumping. In the same summer, on September 20, 2008, in jumping in Villach , he achieved his only podium finish in the Continental Cup as third . Fettner continued to take part in the Continental Cup , but without any notable successes, which is why he was not accepted into the A-squad for the World Cup . In the spring of 2009 he ended his career. He competed again at the Universiade 2011 in Erzurum , Turkey , finishing eighth on the normal hill and eleventh on the large hill in the front of these student world games.
Nicolas Fettner is the brother of the ski jumper Manuel Fettner and the Nordic combined athlete Julian Fettner .