Prior to LSSU: A 2023 NHL Draft selection, Round 7, #214 (BOS), he flew onto the radar with a massive season Västerås IK J20... He scored 23 goals with 17 assists in 48 games at the J20 Nationell level while captaining the team... He also made his senior level debut for Västerås in HockeyAllsvenskan, the second division of Swedish hockey... That season, Nassen also competed for the Swedish U19 and U20 international teams... After he was drafted, Nassen moved to Frölunda HC J20, where he posted 31 points in 41 games... In 2024/25, he moved to the US and played in 34 games for Miami University, scoring six goals. He chipped in another six with 12 assists as a sophomore... At 6'4", 214 pounds, he brings a heavy game and a nasty shot.