It seems like there are lot of guides here on installing Nextcloud, and a number of people reporting problems with many of them. So, I figured, why not write another one? This is inspired by the work of @kjake in his scripts to build jails for Unifi and Crashplan, and largely follows the process that @dureal99d documented...
Scripted installation of Nextcloud 18 in iocage jail
Scripted installation of Nextcloud 18 in iocage jail