Open a terminal and issue prime-select query - what's displayed? You may need to change your performance setting to either 'nvidia' or 'amd' to specify which GPU to use. My ZenBook has both Nvidia and Intel - if 'intel' is set, it's like a power saving mode - and if 'nvidia' is set, all-out performance settings. You may be seeing the AMD one being 'used' because of GPU switching - if it's in 'on-demand', you'll use the liter AMD GPU (assuming the AMD is weaker) for less intensive processing, and when more pow-a is needed, it switches to the Nvidia GPU. I normally have 'on-demand' set, partly cause I don't do a lot of intensive graphics stuff. When I'm using Cura and other modeling apps, definitely use the Nvidia setting so it doesn't skip or lag..
The Nvidia app should also display this info under 'Prime' settings; toward the bottom of the list on the left column.