He was a member of the winning Continental European Team in the 2017 Jacques Léglise Trophy against Great Britain and Ireland.

He appeared in the European Amateur Team Championship four times and won the 2019 event at Ljunghusen Golf Club with Albin Bergström, Vincent Norrman, Christoffer Pålsson, Pontus Nyholm and Ludvig Åberg.

Nyfjäll won the bronze at the 2020 event in the Netherlands together with Gustav Andersson, Albin Bergström and Vincent Norrman.

Amateur at Oakmont Country Club, after triumphing in a 12-man playoff for the last match play spot.

In 2022, Nyfjäll won the Big Ten Championship, the only golfer in the 72-man field to finish the weekend under par, becoming Northwestern's first medalist at the event since David Lipsky in 2010.