Unfortunately it’s still down: https://developer.nvidia.com/registered-developer-programs
[i]Registered Developer Programs
We are in the process of a major update to the NVIDIA Developer Portal. During this time user profile changes and new signups are closed.
The URL you tried to access may require you to login or requires membership to one of our registered developer programs. If you are a member please login - using the link at the top right of the web page.
Should you want to extend your membership or sign up as a new member - we apologize for any inconvenience and request you try again in a few hours.
Thank you for visiting NVIDIA Developer.[/i]