For example, our stack is nginx, uwsgi, django, elasticsearch, and postgres. Installing most of the pieces seemed relatively straightforward(though required a fair bit of searching through the nixpkgs source), but it's honestly pretty unclear how to install our actual django app.
Currently we just clone the repo to the server and point uwsgi to the relevant uwsgi.py file, but it doesn't seem like there's a good way to do that in NixOS.
I'd love to hear that I'm wrong here, but again, the lack of decent example documentation is really the single biggest issue I have with NixOS. The rest of the documentation seems to be improving slowly but steadily.