His grit and intensity, especially among the boards, earned him the role of a dependable checker with the ability to add the odd goal/assist.

A talent of Djurgårdens IF in Sweden, Nilson moved to North America in 1998 and played most of his first two years in the American Hockey League.

After three full seasons with the Panthers, he was traded to the Calgary Flames on March 8, 2004, for a second round draft pick (used to select David Booth).

In the summer of 2008, the Flames placed Nilson on waivers and after clearing without being claimed by another club, he was loaned to Lokomotiv Yaroslavl of the Kontinental Hockey League (KHL) for the season.

Nilson kept producing points during the playoffs and Djurgården reached the finals against HV71, which they lost four games to two.