as far as I remember when I scratched my head on it, three major points:
a. enable early KMS in your initramfs of choice, reference here
b. for a reason beyond my understanding, GDM requires the nvidia-suspend.service , nvidia-hibernate.service and nvidia-resume.service to be enabled in order to switch to Wayland session, reference here in ArchWiki plus the issue explained in Gnome’s gitlab
c. from the same link pointing to ArchWiki, enable NVreg_PreserveVideoMemoryAllocations and set NVreg_TemporaryFilePath options of the nvidia kernel module, via a modprobe file; this is necessary to handle (more or less) properly the suspension/hibernation.
After all this, Gnome should offer you Wayland as default session, with Xorg as an option selectable on login.
Bear in mind this does not guarantee hibernation/suspension will work flawlessly; I can only bring my personal experience to the table, but very often resume from suspension is accompanied with graphical artifacts (I called them GDM listening to Cerrone 
), while hibernation doesn’t work at all, and I still have to understand the problem.
Good luck with it, and let us know if something’s missing 