Fix config
vim nabble/conf/Init.luan
replace ubuntu.nabble.com:8080 with your domain (example for ubuntu.nabble.com)

Configure nginx
apt-get install nginx
change ubuntu.nabble.com with your domain
cp nabble/nginx/ubuntu.nabble.com /etc/nginx/sites-available/
ln -s /etc/nginx/sites-available/ubuntu.nabble.com /etc/nginx/sites-enabled/
/etc/init.d/nginx restart

Check nginx
run nabble: ./rever.sh
open in browser http://ubuntu.nabble.com/free-forum.html

SSL
snap install --classic certbot
ln -s /snap/bin/certbot /usr/bin/certbot
certbot --nginx -d ubuntu.nabble.com
open in browser https://ubuntu.nabble.com/free-forum.html