2011-12: John Nyberg skated for the Frolunda U18 and U16 teams in Sweden and played for Goteborg in the TV-Pucken tournament for high school players. He had no points and was minus-4 with no penalties in 12 games for the Frolunda U18 team. Nyberg scored 1 goal with 4 assists and was +11 with 6 penalty minutes in eight games for the Frolunda U16 squad. In eight games during the TV-Pucken tournament he was +4 and had 2 assists.
2012-13: Nyberg spent the season with the Frolunda U18 team. He scored 4 goals with 10 assists and was +16 with 36 penalty minutes in 40 regular season games as Frolunda finished third in the South Division. Nyberg was minus-1 with no points and 2 penalty minutes in three playoff games.
2013-14: Nyberg played 19 SuperElit league games with the Frolunda U20 team and was the top scorer amongst defensemen in the U18 Elit League South Division. He scored 1 goal with 3 assists and was +8 skating for the Frolunda U20 team. In 33 regular season games for the Frolunda U18 team Nyberg scored 11 goals with 27 assists and was +27 with 32 penalty minutes. Frolunda captured the U18 bronze medal and in five playoff games Nyberg was minus-3 with 2 goals and 12 penalty minutes. Not among the 140 international skaters in the Central Scouting final rankings he was selected by Dallas in the sixth round (165th overall) in the 2014 NHL Draft.
2014-15: Nyberg appeared in 17 regular season SHL games with Frounda as an 18-year-old and skated for Oskarshamn in AllSvenskan. He was one of the top defensemen for Frolunda’s U20 team. Nyberg had 1 assist and an even plus/minus, averaging eight minutes of ice time with Frolunda. In nine AllSvenskan games with Oskarshamn he had 1 assist with 2 penalty minutes. An assistant captain for the Frolunda U20 squad, he scored 7 goals with 10 assists and was +1 with 26 penalty minutes in 25 regular season games. Frolunda captured a silver medal, reaching the SuperElit finals. Nyberg scored 1 goal with 1 assist and was -2 with 16 penalty minutes in eight playoff games.
Nyberg is a rangy, offensive-minded defenseman who can quarterback a power play effectively. He is still fairly raw in terms of defending and positional play but has a big shot and likes to be involved in the attack. His height suggests he will have the prototypical size to be an effective defender once he adds some bulk and strength.
Nyberg has spent most of the 2015-16 season with Oskarshamn in AllSvenskan — skating in a handful of SHL games with Frolunda and playing for that club's U20 team. He was with the Sweden U20 team prior to the 2016 World Juniors but did not make the final roster. Yet to sign an entry-level contract with the Stars, Nyberg continues to put the elements of his game together but as with any late round pick is still a mystery in terms of his long-term potential. He projects to being an effective, offensively-inclined defenseman at the NHL level but has significant strides to make before reaching his potential.