Career
His last club was Fremad Amager in the Danish 2nd Division East. Between 2002 and 2009, he played 64 matches for Sweden and scored three goals. He is called "MiNi" by Swedish supporters, referring to the first letters in his first and second names.
Nilsson started his career with Ovesholms IF, where he stayed until 1998 when he moved to Åhus Horna BK. He played for the club for only one season before moving to Halmstads BK in 2000.
His first season was mostly spent on the bench, but eventually he became one of the team"s more important players until, during the 2004 season, he was sold to English club Southampton. On 4 March 2008, he stated that when returning to Sweden he would play for Halmstads BK, but he would live in Malmö since he wanted to live in a larger city.
On 8 April 2009, Nilsson announced a transfer to Brøndby IF. He signed a three-year contract and will move to the club on 1 July 2009. Nilsson"s Brøndby contract expired on 30 June 2012 after which Nilsson left the club following three years playing as both a right back, midfielder and occasionally right midfielder.
In his last six months at Brøndby, Nilsson did not play much as Brøndby did not see Nilsson as part of the club"s future.
In August 2012 he agreed to play for the Copenhagen-based club Fremad Amager due to the new assigned coach Per F. Hansen, as he was the former assistant coach of Brøndby IF. Although on 8 August 2012, Nilsson officially announced his retirement as a player. He has played in the Sweden national team since 20 November 2002, when he made his debut against the Czechoslovakian Republic in which he scored two goals in a 3–3 draw. He started out as a midfielder, but once when the national team lacked defenders, Nilsson was moved back, since when he generally plays as a defender for the national team
Nilsson made a terrible mistake that caused Sweden to lose 0–1 and eventually miss the World Cup.
A cross came in from the right and Nilsson was going to clear it out of Swedish penalty area. He was not under pressure when the ball came.
Somehow, he managed to get the ball on his left leg, causing it to roll across the goal-line and to the Danish midfielder Thomas Kahlenberg who scored easily. International goals Club.