The breach comes with some good news and some bad news. The bad news is that Nvidia's early investigation has concluded hackers managed to steal usernames, email addresses, passwords and public profile information.
The good news is that Nvidia actually encrypts their stored passwords, which means only hashed passwords with a random salt value were accessed. As a precautionary measure, Nvidia is reseting all forum passwords and advising users to change identical passwords on other websites.
Since email addresses were accessed, Nvidia stresses users not to give sensitive information to anybody impersonating an Nvidia employee over email.
Nvidia will keep us updated on the status of the forums here.