I wanted to reply just as an update as I finally got round to migrating my Nextcloud instance to be behind nginx, and should anyone else stumble upon this thread maybe this will help you.

I think you misunderstood my question btw but don’t worry, I figured it out anyway.

My question was about whether or not I could transfer my Nextcloud instance (including data) to be behind a reverse proxy. The answer is simply yes, you can use the same Docker volumes and it’ll be the “same” Nextcloud instance (ie exact same config, user data, etc, no need to set anything up again).

If you’ve already followed these instructions on a server that doesn’t already have a web server running, just take your containers down and follow Nextcloud AIO’s reverse proxy guide. If you use the commands suggested in both guides, the volume names will be the same, so the new docker container will use the same volume that the old docker container used. You’ll have to delete or rename the old containers so Docker doesn’t complain about a container by the same name already existing.

Thank you! That’s very helpful.

As an aside/follow up question, I set up Nextcloud with their all in one container. I see they’ve got separate instructions for setting it up behind a reverse proxy. Is there a need to start from scratch and follow the reverse proxy instructions or can I somehow transfer my Nextcloud instance to be behind a reverse proxy?