Career
He is currently playing for the Saint Louis Blues of the National Hockey League (National Hockey League). Nilsson was drafted 62nd overall by the Islanders in the 2009 National Hockey League Entry Draft. On 27 April 2011, the New York Islanders signed Nilsson to a three-year entry-level contract.
He made his National Hockey League debut on 19 November 2011, against the Boston Bruins, in relief of Rick DiPietro.
He let in 3 goals on 17 shots, while playing 40 minutes, as the Islanders lost 6-0. He got his first start in the National Hockey League on 21 November 2011, against the Pittsburgh Penguins at Consol Energy Center in Pittsburgh, Pennsylvania.
In his next start, on 10 March 2012, he almost shutout the Devils a second time, but the Devils scored two goals in the last two minutes of the game, resulting in a 2-1 loss for the Islanders. Nilsson saw limited action with the Bridgeport Sound Tigers in 2012-2013, as he was diagnosed with an unknown, fatigue-inducing illness in January 2013.
The illness was later determined to be a vitamin B12 deficiency.
Nilsson spent much of the 2013-2014 season as the Islanders" backup goaltender. On 26 May 2014, as a restricted free agent, Nilsson decided to sign a contract with Russian club, Ak Bars Kazan of the Kontinental Hockey League. Ak Bars issued a release confirming the signing.
On 4 October 2014, Nilsson"s National Hockey League rights were traded by the Islanders to the Chicago Blackhawks in a trade for Nick Leddy.
On 6 July 2015, Nilsson"s National Hockey League rights were traded for a second time, from the Blackhawks to the Edmonton Oilers in exchange for prospect Liam Coughlin. He in turn agreed to a one-year, one-way contract with the Oilers.
Nilsson earned a spot on the Oilers roster after a stellar training camp, not allowing a single goal in the preseason. In the 2015-2016 season, Nilsson appeared in a career high 26 games with the Oilers, sharing the pipes with Cam Talbot, before he was traded approaching the trade deadline by the Oilers to the Saint Louis Blues in exchange for Niklas Lundström and the Blues fifth round selection in the 2016 National Hockey League Entry Draft on 27 February 2016.
Nilsson represented Sweden at the 2010 World Junior Ice Hockey Championships which were held in Saskatchewan, Canada.
He only played in one game during the tournament, as Jacob Markström was the starter.