I didn't realize that nginx-plus doesn't give the rpm system a provides nginx. This means if your program is configured to only require nginx, it may complain and say it's not there.
This is a pretty easy fix though, you simply need to download the rpm, modify and install it locally.
yumdownloader nginx-plus
rpmrebuild -enp nginx-plus-*.rpm
This should open the SPEC file for editing, you'll see lines showing provides and requires. At the top of the provides simply add Provides: nginx using spaces
Conflicts: nginx
Obsoletes: nginx
Obsoletes: nginx-plus-debug
Provides: nginx
Provides: config(nginx-plus) = 20-1.el7.ngx
Provides: nginx-plus = 20-1.el7.ngx
Provides: nginx-plus(x86-64) = 20-1.el7.ngx
Provides: nginx-plus-r20
Provides: webserver
Substitute the correct version above and below
rpm -Uvh ./rpmbuild/RPMS/x86_64/nginx-plus-*.rpm
And that's it, you have nginx-plus providing nginx as needed.