Internal network and trusted certificates with Collabora

Hi there.

Id like to know if there is a solution to nextcloud using Collabora within the internal network and removing the “not secure” notification on my browser.

Basically I have a Rpi4 running opensuse tumbleweed with docker, then nextcloud and Collabora.
My nextcloud instance Is behind an nginx proxy manager which is accessible though my domain “sub.wormhole.net
Using the nextcloud instance is fine and the certificate is valid but I configured my nextcloud instance to use Collabora from my internal network 192.168.1.12:9980.

It works great but my chrome browser then complains about the website not being secure after opening a document with Collabora. Id just like to get rid of that.

I hope these screenshots make sense.