proxy server with for port 3000 with ssl enabled

nginx.conf

  GNU nano 4.8                                                            metabase.com                                                                      # sample nginx.conf
# proxy requests to Metabase instance
server {
  listen 80;
  listen [::]:80;
  listen 443 ssl; # managed by Certbot

  ssl_certificate /etc/letsencrypt/live/metabase.covidindiaresources.com/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/metabase.covidindiaresources.com/privkey.pem;

  server_name metabase.covidindiaresources.com;
  location / {
    proxy_pass http://127.0.0.1:3000;
  }

    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot

    # Redirect non-https traffic to https
    if ($scheme != "https") {
        return 301 https://$host$request_uri;
    } # managed by Certbot
}

Guide to create ssl-cert with certbot.
While creating ssl cert, it's probably important to link to actual domain (not sure about this).