NVIDIA GeForce Now
Is NVIDIA GeForce Now safe to download and use in an IMac Computer? Is there a risk for a virus to be installed or for information to be stolen from the computer ?
If it's a driver for the GPU, then do not install it. The most current driver for your GPU is contained in the most recent version of macOS you have installed.
I would seriously doubt that Nvidia software would contain a virus. To be safe only download the software from Nvidia. Also, check its compatibility with your model before installing it.