addon-nginx-proxy-manager VS iocage-homeassistant

Ok, I'm not familiar with how it specifically integrates with HA, but did you go through the install guide here? It looks like there might be a button to open the web UI.

There’s a community maintained proxy manager addon so installing would be easy and you could spend more time teaching nginx skills.

i have home assistant installed running nginx pm as an "addon" (https://github.com/hassio-addons/addon-nginx-proxy-manager)

Way back when, if you installed HA Core as a TrueNAS CORE Community Plugin, hopefully you followed these instructions to store your homeassistant_config directory to an external dataset. It will make your migration will be pretty easy.

Home Assistant

That leaves the Home Assistant Core installation option. TrueNAS has a community plugin that will take care of the jail setup and installation. You can find it from the plugins page in TrueNAS after changing the collection from iXsystems to Community. Here's a thread about the plugin, instructions for storing the data outside the jail, and instructions for setting up an SMB share for the HA data. (I don't like how the SMB instructions make the share readable by anyone. I'd suggest not checking the read-only option and replacing the write list=@homeassistant auxiliary parameter with valid users=@homeassistant so that only members of the homeassistant group have access.)