The recommended way to do this is:

server {
    listen       80;
    server_name  example.org;
    return       301 http://www.example.org$request_uri;
}

server {
    listen       80;
    server_name  www.example.org;

    location / {
        proxy_pass MY_IP_SERVER:8080;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
    }

Replace example.org with your domain name.