Update: Leak is related to nuggetbridge hack that occurred. Usernames that are effected can be found here:https://t.co/3USWuAsWIh
— Push🎃In (@PushDustIn) January 23, 2017
UPDATE: So this appears to be related to a hack of a different site.
It’s just come out that roughly 450 Nintendo Network accounts have been compromised. This appears to have been done through people that use the same password on multiple sites. It seems to be a phishing scam and not as a result of directly compromising Nintendo’s servers. A list of the accounts, without passwords, was posted here.
No matter how it happened, it’s a good idea to change your password for not only your Nintendo Network account but anything else that uses the same username and especially password. But you shouldn’t be using the same password for multiple sites anyway.
I’ll say it again: This does not appear at all to be a breach of Nintendo’s servers.