Is that all I need just to proxy through nginx, that's what I'm currently doing, I saw that plugin in settings and thought I was doing something wrong. I just wanted to confirm I'm doing everything properly.
Yup! I used the instructions here: https://docs.nodebb.org/configuring/proxies/nginx/
There is an example block with SSL in use there. No plugin needed. I use LetsEncrypt for free certs.