Anybody selling an old Nuendo 4 for mac with code

The license is not on the computer, but on you eLicenser dongle.
Which would still work. Just install Nuendo on your machine, even if it’s a mac, plug the dongle in and you are in business.
And any newer eLicenser (Nuendo, 5,6,7,8) allows you to run any older Nuendo version.

Fredo