The day after Nyby graduated from Van Nuys High School in California in 1959, he drove to north central Idaho, following a friend to the University of Idaho for college. He stayed at Idaho for two years as a member of the swim team and the Tau Kappa Epsilon fraternity before transferring to USC. In 1963, the Air Force sent Nyby to Vietnam as a photographer. Four years later, he landed a job as an assistant director; his first directing job was an episode of Ironside (1967). In the years since, he has directed television movies and episodes of many television series, counting his Hill Street Blues (1981) episodes as his favorites.