2010-11: Joni Nikko made the jump from Division 1 hockey in Finland to the elite SM-Sarja level of juniors and played for Finland's U17 team at the 2011 World Hockey Challenge. After scoring a pair of goals in a 2010 U20 relegation playoff game for Vaasa Sport during the spring, he moved up to Lukko in Rauma; splitting the year between the U20 and U18 squads. Nikko scored 4 goals and was -5 with 6 penalty minutes in 16 games (including one playoff contest) for Lukko's U20 team. He was a top scorer for the Lukko U18 team; finishing with 16 goals, 25 assists and 16 penalty minutes in 26 games. Nikko had no points and 2 penalty minutes in five games for Finland at the WHC.
2011-12: Nikko made his pro hockey debut in Finland's SM-Liiga — appearing in one game for Lukko Rauma — and was the second-leading scorer for the club's U20 team behind Czech winger David Stach. In 42 games he scored 13 goals with 22 assists and was +9 with 45 penalty minutes. Nikko was ranked 84th amongst European skaters in Central Scouting's final rankings prior to the 2012 NHL Draft but was not selected.
2012-13: Nikko was one of the top players for the bronze medal-winning Lukko Rauma U20 team in the playoffs after missing much of the year due to injury and skated for Finland's U19 team. He played 12 games during the regular season — scoring 8 goals with 5 assists and finishing +4 with 6 penalty minutes. In ten playoff games he scored 6 goals with 2 assists and was +3 with 14 penalty minutes. In seven games with Finland's U19 team he scored 1 goal with 3 assists and was -1 with 14 penalty minutes.
2013-14: Nikko emerged as an offensive threat for Lukko Rauma as a rookie in Finland's Liiga and skated for the gold medal-winning squad at the 2014 World Junior Championship. In his first 36 games he scored 9 goals with 8 assists and was an even plus/minus with 10 penalty minutes. Playing in a lower line role at the WJC he scored three goals, including a key goal in Finland's semifinal win over Canada, and was even with 2 penalty minutes in seven games. He also played three games for Lukko's U20 team and was +1; scoring 2 goals with 5 assists. Nikko was ranked 84th amongst European skater in Central Scouting's mid-term rankings prior to the 2014 NHL Draft.
Nikko is the epitome of a late bloomer whose size and strength make him an intriguing prospect. A goal scorer at the junior levels, Nikko is opportunistic more so than overly skilled and his skating agility is suspect. His two-way game has improved greatly since his early junior days when he was perceived as an offense-only player. Not overly physical despite his size, Nikko will block shots and do the little things to help his team win.
Nikko has been impressive in his first pro season in Finland's Liiga but determining how high of a ceiling he has in terms of developing is difficult to gauge. A dominant player at the junior level due in part to his size, Nikko has worked to improve the areas of his game that needed improvement but will be 20 when the 2014 NHL Draft takes place. Long-term, his optimum potential is as a lower line two-way forward who can play in all situations and occasionally score goals.