Nykkelmo watched the 1974 Norwegian Championships, which were held in Selbu, which influenced her to train in competitive skiing. She won four medals at the
1985 FIS Nordic World Ski Championships in
Seefeld with a gold in the 20 km, a silver in the 4 × 5 km relay, and bronzes in the 5 km and 10 km. At the 1991
Biathlon World Championships in
Lahti, she won a gold medal in the 7.5 km sprint and silvers in the 15 km individual and the 3 × 7.5 km relay. Nykkelmo won the
Egebergs Ærespris in 1990 for her achievements. After she finished her competitive career, Nykkelmo became a board member of the
Norwegian Sports Confederation from 1999 to 2003. ==Cross-country skiing results==