My CentOS7 install placed Nginx in a unique directory.
The installation worked:
/usr/bin/certbot -vvv --nginx --nginx-server-root /etc/opt/rh/rh-nginx112/nginx
However, trying to setup the renew with:
certbot -vvv --nginx-server-root /etc/opt/rh/rh-nginx112/nginx renew --dry-run
I got a Could not choose appropriate plugin: The nginx plugin is not working; there may be problems with your existing configuration. The error was: NoInstallationError()