We've already seen a hint at this from Switch previews, but Nintendo provided details now.
Main points:
- Each card can be registered only to one account
- Registration only within two years of release (does not apply to digital purchases!)
- Big reduction in points compared to digital purchases:
https://my.nintendo.com/missions
Complete this mission by registering a Nintendo Switch game card to your Nintendo Account. You can do this directly from the HOME Menu of your Nintendo Switch. Press the + or - Button while the icon of the game you want to register is selected. Then go to "My Nintendo Rewards Programme" and select "Earn Points".
Which mission is completed is determined based on the Nintendo eShop value of the respective game at the time of registration. If the game is not listed for sale in Nintendo eShop, it qualifies for the highest point mission (you earn 16 Gold Points).
Each Nintendo Switch game card can be registered only once. If your game card was registered to a different Nintendo Account before, you will not be able to register it anymore. If you can't register a game card you purchased as someone else did so already, please contact the retailer you purchased it from for support.
A game card can be registered within two years from the official release day of the game in your country. You can confirm the release date of a game by visiting its details page on Nintendo eShop.
Main points:
- Each card can be registered only to one account
- Registration only within two years of release (does not apply to digital purchases!)
- Big reduction in points compared to digital purchases:
https://my.nintendo.com/missions