nginx-plus installation

nginx-plus-install.sh

mkdir /etc/ssl/nginx 
wget -P /etc/ssl/nginx/ https://cs.nginx.com/static/files/CA.crt

## move nginx-repo.crt  to /etc/ssl/nginx/nginx-repo.crt
## move nginx-repo.key  to /etc/ssl/nginx/nginx-repo.key

wget http://nginx.org/keys/nginx_signing.key 
apt-key add nginx_signing.key
apt-get install apt-transport-https libgnutls26 libcurl3-gnutls
printf "deb https://plus-pkgs.nginx.com/ubuntu `lsb_release -cs` nginx-plus\n" >/etc/apt/sources.list.d/nginx-plus.list
mv  /etc/apt/apt.conf.d
wget -P /etc/apt/apt.conf.d https://cs.nginx.com/static/files/90nginx
apt-get update
apt-get install nginx-plus

@idanzam may be https://docs.nginx.com/nginx/admin-guide/installing-nginx/installing-nginx-plus/ can help