Nyborg, who started for Hedmark, won the bronze medal with the relay at the 1948 Winter Olympics in St. Moritz . He also achieved 17th place over 18 km there. The following year he finished ninth over 50 km at the Holmenkollen Ski Festival . At Norwegian championships he won in 1947 with the relay and in 1949 over 30 km. In 1946 he was second with the relay, in 1948 third with the relay and in 1949 third over 50 km.