Simply redirect a domain to a port. For example, if you wanted to visit: lukeshirnia.co.uk:5050 you can use a sub domain with proxy pass do this on local host.
<sxh bash>
server {
        listen 80;
        server_name example.lukeshirnia.co.uk www.example.lukeshirnia.co.uk;

        location / {
                proxy_pass http://localhost:5050;

}
}
</sxh>