Making ExpressJs recognise base path

I have built an small nodejs app using express. Everything works fine on my local machine & the app runs good when I point my browser to http://localhost:3000

But now I am planning to host this app on one of the domain, Lets say http://example.org which is running on nginx & its a php code

But how do I make my express app to properly run the app on example.org/nodeapp ? Currently, it is considering the example.org as base url of my app & hence throws 404 as it searches for nodeapp in my routes. It should ideally consider example.org/nodeapp as baseurl.

In my server block config, I have following code

listen 80;

server_name your-domain.com;

location /nodeapp {
    proxy_pass http://localhost:3000;
    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;
}