Thank you for sharing the configuration how you put the Nginx in front of Jitsi.
I tried exactly the same way and for some reason it isn't working for me. The original post is a little old. Hence, let me ask you whether it still works for you. And let me know whether you added something in the configuration for a newer Jitsi version.
If the installation is behind a proxying nginx server, remove /etc/nginx/modules-enabled/60-jitsi-meet.conf. Then go to /etc/nginx/site-available/your-conf and change it to listen on 443 instead of 4444 and restart nginx.
I did that on my jitsi vm and now it works like a charm. The nginx reverse proxy config above is still enough for the current jitsi version.
From my end there was nothing to do with the stuff about NAT (the restart of the jitsi vm was enough).
I hope it helps someone else. The nginx reverse proxy gives me the opportunity using multiple applications behind ports 80/443 at home.