CentOS install nginx

# vi  /etc/yum.repos.d/nginx.repo

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

# yum install nginx -y

# /etc/init.d/nginx restart

Reference :
Install
RHEL / Centos 6: Install Nginx Using Yum Command