/etc/yum.repos.d/nginx.repo

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/6/x86_64/
gpgcheck=0
enabled=1

 (

[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=0
enabled=1

)

find repo from http://nginx.org/packages

yum install nginx

(yum update)

nginx