Unixcop published a tutorial showing you how to use Nginx as a load balancer.

Using Nginx As A Load Balancer

The following is a tutorial for setting up Nginx to act as a load balancer between our servers. This is also the final part of my Nginx series. Throughout this series, I’ve mentioned that Nginx is really just a reverse proxy. 

Using Nginx As A Load Balancer - Unix / Linux the admins Tutorials