Yes, it is possible to run the Dolby Atmos Production Suite on a Mac, and your Nuendo on a PC. The two computers need to be in the same Network (to transmit Atmos object metadata), and in addition you need to physical transmit up to 128 channels of Audio between the computers. Very common is to do the audio connection via DANTE. But MADI, Ravenna or other digital audio formats work as well, depends on your interfaces and studio infrastructure.
Did you had a look at our Webinars on "Setting up your Studio"?
Regarding Dolby Vision:
Tidal and Amzon HD are streaming *music* in Dolby Atmos - you can´t deliver Dolby Vision content to these services.
This forum is on Dolby Atmos only - if you want to learn more on Dolby Vision please have a look on these pages:
The Webinar I linked above mentions some interfaces with 12+ outputs.
You could also look into going DANTE out of the Mac and purchase a DANTE-to-Analog converter to go to the speakers. (again, the choice of devices is limited but there are a few).
enjoy checking out Dolby Atmos, best, David
Sorry, missed that part of the question.
Our binaural headphone rendering happens in the software. As such, your choice of headphones doesn´t matter. I recommend a good quality, linear sounding headphone that you´re comfortable wearing for longer periods of mixing time.
I don´t have any experience with the Dolby Dimension Headphones, can´t comment on those.