Bottom Line. You can successfully run G-Sync on a FreeSync monitor if it's on Nvidia's approved list. You'll have to give up HDR and overdrive to do so, but it works fine otherwise.

Are G-Sync and FreeSync compatible?

NVIDIA's "G-Sync Compatible" program expands its variable refresh rate (VRR) reach, welcoming monitors that are compliant with the VESA DisplayPort Adaptive-Sync standard, including AMD FreeSync. NVIDIA tested hundreds of monitors and certified those that deliver a leading G-Sync experience.

What FreeSync monitors work with G-Sync?