With the recent release of OS X 10.11.1 & the 10.10.5 security update (14F1021), Nvidia have released corresponding Web Driver updates to keep their latest GTX 9XX & TITAN X working within the OS X environment.
Find the relevant drivers below and remember to ensure that you have a Mac EFI GPU installed in your system when updating your OS X version & Nvidia Web Driver version.
OS X 10.11.1: Download Driver
OS X 10.10.5 (14F1021): Download Driver
If you have any issues, just let us know in the comments below.