In 2002 he played second for Eric and finished second- losing to Canada's David Hamblin in the final.

In 2003 Carlsén picked up another silver medal losing to Steve Laycock of Canada.

The team won the gold medal, beating Stefan Rindisbacher of Switzerland in the final.

In 2005 Nils was skipping the Swedish junior team, and he picked up another silver medal losing to Canada's Kyle George in the final.

In 2006, Nils skipped Sweden to another silver medal losing to Canada's Charley Thomas.