The nginx_install.sh installs NGINX and configured Reverse Proxy. For configuration of domain signed / public certificates, you need to copy the certificates in the host machine and configure their path in https.conf file. Following script demonstrates the procedure.
If NGINX throws an error while restarting where SELinux is set to enforcing mode, run following commands in bash
For configuration of Chain Certificates, follow Digicert SSL Configuration Guide for NGINX, section How to Install and Configure your SSL Certificate. Verify your chain certificate bundle by any available tool e.g. KeyCDN.