How to configure nginx for heroku nodejs web application

node.js nginx heroku

Good starting point : heroku/heroku-buildpack-nginx

What you are looking for is rate-limiting with NGINX, read this for a better understanding

and here you have an example gist: NGINX reverse proxy with rate limiting

This is the file of the heroku-nginx-node-example that I think you have to add the limit_req options

If you need more help, show what you have tried so far and I will edit this answer.