I have the below configuration
Firebase - for hosting (serving static files) and storing data (Database).
Nodejs - for making API calls to Firebase, Twilio and Sendgrid.
Angularjs - for frontend
Do I need Nginx for the above configuration ? looking at answers like these makes me consider Nginx.
My app is intended to serve several hundred users.
No, you do not NEED nginx. There are zillions of node.js apps at the scale you describe that do not need to use something like nginx.
You would use Nginx if you had a specific problem in your deployment and Nginx was the easiest/best way to solve that problem. You have not described any specific problem (other than scaling to a few hundred users which node.js can do just fine by itself) so you have not described any reason that you need Nginx.
Nginx has a bunch of things it is great at, but until you identify a specific need for more than node.js offers, I would not recommend that you complicate your deployment just because Nginx helps some people. Instead, deploy your app, measure its performance, understand where your weaknesses are and then evaluate if Nginx is the best tool to help you fix any weaknesses that need fixing.
