Laravel nginx.conf with official Heroku php buildpack?
You are missing fastcgi_* directives; try this after your location directive:
location ~ \.php$ { try_files $uri /index.php =404; fastcgi_split_path_info ^(.+\.php)(/.+)$; fastcgi_pass unix:/var/run/php5-fpm.sock; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params;}Source: How to Install Laravel with an Nginx Web Server on Ubuntu 14.04