I am using the default config while adding the specific directory with nginx installed on my ubuntu 12.04 machine.
server {
#listen 80; ## listen
On CentOS 7.0 I had this Access Deined problem caused by SELinux and these steps resolved the issue:
yum install -y policycoreutils-devel
grep nginx /var/log/audit/audit.log | audit2allow -M nginx
semodule -i nginx.pp
Update: Just a side-note from what I've learned while using digitalocean's virtual Linux servers, or as they call them Droplets. Using SELinux requires a decent amount of RAM. It's most probably like you won't be able to run and manage SELinux on a droplet with less than 2GB of RAM.