Nils Holger Wallin was born on October 8, 1913 in Göteborg and made his IFK Göteborg debut in the 1933/34 season, which was also the debut season of team mate Olof Hultfeldt. Wallin was part of IFK Göteborg's youth program before making his debute with the first team, and is as a result of that regarded by the club as a home-grown player. At 20 years, 6 months and 20 days, on April 29, 1934, he took part his first competetive game against IS Halmia in an Allsvenskan game that ended 3–1. He spent one season with the IFK Göteborgs first team, and during his career he played in 5 first team games. Out of these 5 first team games, 5 were Allsvenskan games.
Nils Wallin is with his 5 Allsvenskan games number
393 on the list of those who have competed in most Allsvenskan games for IFK Göteborg. He is the brother of Viktor Wallin. Wallin passed away in 1993, 79 years old.