Nilsen, who started for Bækkelagets SK , had her first international success at the European Youth Olympic Winter Festival 2003 in Pokljuka . There she won the silver medal over 5 km classic. In February 2004 she ran her first race in the Continental Cup in Hommelvik , finishing ninth over the 5 km classic. At the Nordic Junior World Ski Championships in 2004 in Stryn , she was fifth in the 15 km mass start race and fourth in the relay. In the following year, she won the bronze medal in the 5 km freestyle and in the skiathlon and the gold medal with the relay at the Nordic Junior World Ski Championships in Rovaniemi . At the Nordic Junior World Ski Championships in 2006 in Kranj , she won the silver medal in the skiathlon and the gold medal with the relay. She made her debut in the World Cup at the beginning of the 2006/07 season in Gällivare , which she finished in 33rd place over 10 km freestyle. At the following World Cup in Kuusamo , she took ninth place over 10 km in a classic way, her first World Cup points. The Tour de Ski 2006/07 she finished in 24th place. In Oberstdorf she achieved eighth place in the skiathlon, her best placement in the individual World Cup. At the highlight of the season, the Nordic World Ski Championships 2007 in Sapporo , she came 20th in the skiathlon. At the end of the season she finished 54th in the overall World Cup. In December 2008 she was third at the World Cup in La Clusaz with the relay and at the Scandinavian Cup in Lygna over 10 km classic and thus achieved the only podium finishes in these racing series. At the U23 World Championships in 2009 , she won the silver medal in the 10 km freestyle. She ran her last World Cup race at the 2009 World Cup Final in Falun , which she finished in 56th place over 2.5 km freestyle.
Norway
