This is not good news for Nintendo. Before Nintendo established its new online service for the Switch, the company used what was known as the Nintendo Network ID (NNID). Unfortunately, it seems that hackers have managed to obtain access to at least 160,000 NNID accounts, stealing login IDs, passwords, and other user information stored in those profiles.
There is some good news. If you use a completely different password for your NNID and your Nintendo account, then this might not be as big of a deal for you. However, if you are reusing passwords, then there is a chance that the hackers could potentially gain access to your main Nintendo account and could be using your stored payment information to make in-game purchases.
Nintendo has confirmed the breach and has stated that they will be halting NNID logins. They have also since reached out to customers who might have been affected by the breach, and are asking users to enable two-factor authentication to secure their accounts. If you haven’t been notified by Nintendo, you might not have been affected by the breach, but it might be a good idea to update your login information and enable two-factor authentication just in case.
Source Ubergizmo