You would first need to get your LEMP stack setup which can be done using our tutorial:
Then you would need to setup your specific nginx configuration for Magento which can be done following their wiki:
LEMP stack is a group of open source software to get web servers up and running. The acronym stands for Linux, nginx (pronounced Engine x), MySQL, and PHP. This tutorial explains how to install the required repos to download nginx and php-fpm, how to install MySQL, how to install nginx, how to install php-fpm, how to configure php and nginx, and how to create a php info page. This tutorial is written for Ubuntu 12.04.