You do not need a visa to Greenland if you are a Nordic citizen. A visa to Denmark does not automatically give you access to Greenland and you should obtain further information with the Danish Immigration Services. If you travel without a valid visa Air Greenland can deny your boarding without any liability for your onwards journey.
Check out what nationalities are required to have visa to travel to Greenland on www.nyidanmark.dk
You need to be able to identify yourself when travelling, so bring a valid picture id, e.g. your passport.
More information about visas and how to apply can be found on the website of Government of Greenland »
For more information please visit: https://kundeservice.airgreenland.gl/hc/en-us/articles/4902717026588-Passport-Visa-and-Transit-permit