A custom macOS Utilities app.
Bundle this with your NBI. Use something like outset to run it on launch.
This app expects to have 'Install macOS High Sierra' mounted. Due to the laziness of the author, this is hardcoded. If you wish to change the installer version, and kick off app, please make your own changes in your own repository. Sorry.
I'm lazy. Everything is hardcoded. It needed to be simple and easy for me to make quickly. You can easily replace the labels, icons, and paths with whatever you need. Potentially in the future, a config could be pulled from a remote server, but for now, that is not the case.
Currently, the software installation is kicked off by an AppleScript app that calls a bash script to erase the drive and open the High Sierra installer application. If you do not require the drive to be erased, you can replace the path string in the application yourself.