Missing HDMI audio output(device unplugged), NVidia audio card not detected
I had a similar issue with a zotac micro pc with Nvidia card. In the end, mine had nothing to do with the Nvidia drivers. It was a default setting issue in the BIOS. I was able to access the audio settings there. Mine were set to the external (headphone) jack only. I switched audio to the HDMI port, saved and exited.
HTH,