Thanks for the help. Got it working. It turned out to be a problem with three settings.
One: For installing nginx you NEED to use the ix-applications storage option when installing it as an app. Using any kind of host storage option does not work correctly. The helpful video says this “that it does not load” but in my case it loaded and did not actually work correctly. https://www.youtube.com/watch?v=_FcC79zMiJc
Two: Following this super helpful guide TrueNAS Scale Reverse Proxy with Nginx and DuckDNS - DeveloperJose @DeveloperJose Thank you so much. I realized that my nginx ports were not correct at the correct 80, 443. I changed them because it conflicted with the Truenas GUI ports, but the right way was to keep nginx at the default values and change the Truenas GUI (81/444). My dumbass didn’t realize the whole system rests on the proxy working on these ports and I did it backwards by changing the nginx ports.
Three: Just trial and error and I realized the nginx proxy host settings needed to be the following. It differed from the how-to from Jose, and I can’t explain why. But it works for all my apps for me. YMMV:
Finally got this working, although a lot of this was not intuitive. Thought I would post this to steer this to Jose’s helpful how-to.
You’re doing God’s work Jose for noobs like me!