Approach 1:

yum install nginx
systemctl start nginx
systemctl enable nginx
nginx -V

Approach 2 (Recommended):

Documentation Referred:

https://www.nginx.com/resources/wiki/start/topics/tutorials/install/

yum -y install wget
wget https://nginx.org/packages/centos/8/x86_64/RPMS/nginx-1.20.1-1.el8.ngx.x86_64.rpm
yum install nginx-1.20.1-1.el8.ngx.x86_64.rpm
systemctl start nginx
systemctl enable nginx
nginx -V