Dont kill yourself over this. This is normal!
Remember On stand still your Z is not getting cool air compared when you are running. So it gets hotter when not running.
This is normal for it to go 200-220 temp which is actually the norm operating range.
Get a oil cooler if this bothers you.
So hold your horses with warranty and declaring war to Nissan otherwise they will just laugh at you and say "Thank you for enjoying your Z as it runs very good when driven and not on stand still!
