Setup an nginx reverse proxy with ssl.

nginx.conf

server {

  server_name: you.domain;
  listen 443 ssl;
  
  ssl_certificate /etc/nginx/ssl/nginx.crt;
  ssl_certificate_key /etc/nginx/ssl/nginx.key;

  location / {
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_pass http://127.0.0.1:3000;
  }
}