I had hoped the changes in the latest Nvidia driver (which you already have installed below) would help with issue related to suspension, but it appears it has not helped in your case. Quite a few people with Nvidia drivers have had either problems getting the computer to suspend or getting the system to resume from suspension.
Graphics:
Device-1: NVIDIA GK104 [GeForce GTX 760] vendor: Gigabyte driver: nvidia
v: 470.74 bus ID: 01:00.0 chip ID: 10de:1187
In
this post roblm mentions using
sudo systemctl suspend
to suspend. Here is an explanation of the difference
pm-suspend vs systemctl suspend?. Mint uses systemd, so I would presume
sudo systemctl suspend
is the preferred command.
I do not yet know enough about how the Mint buttons are coded to know if something else can be done to get around this issue. Maybe someone else will know.