It depends on what you have processing your PHP code in our case we have a writeup on getting a LEMP stack up and running using php5-fpm to process PHP.

You can find the full writeup here:
https://www.digitalocean.com/community/articles/how-to-install-linux-nginx-mysql-php-lemp-stack-on-ubuntu-12-04

The nginx config file would be setup as follows in that case:

server {
listen 80;


root /usr/share/nginx/www;
index index.php index.html index.htm;

server_name example.com;

location / {
try_files $uri $uri/ /index.html;
}

error_page 404 /404.html;

error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/www;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
#fastcgi_pass 127.0.0.1:9000;
# With php5-fpm:
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
include fastcgi_params;

}

}

I got this message when I restarted nginx: configuration file /etc/nginx/nginx.conf test failed

This was the message:Restarting nginx: nginx: [emerg] unexpected end of file, expecting "}" in /etc/n ginx/sites-enabled/default:121