restore nginx /etc/nginx/nginx.conf , How To Install Linux, nginx, MySQL, PHP (LEMP) stack on Ubuntu 14.04
To recreate it, first uninstall using purge to remove even configuration files and records:
sudo apt-get purge nginx nginx-common nginx-full
then reinstall:
sudo apt-get install nginx
sudo service nginx start
sudo service nginx stop
sudo service nginx restart
How To Install Linux, nginx, MySQL, PHP (LEMP) stack on Ubuntu 14.04
https://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mysql-php-lemp-stack-on-ubuntu-14-04#5-create-a-php-file-to-test-configuration