How can I add a custom prometheus exporter?

I have already got it packaged but the service module seems a bit complicated. I found the doc here but I don’t want to fork nixpkgs yet because I’m still quite new to the nix world, but this seems the only option I got. Is it possible to use overlay or even lighter way to do it?

Thanks!

BTW. I’m trying to add ths exporter.

How about this? How to Setup Prometheus, Grafana and Loki on NixOS - Xe Iaso
Check the Node Exporter Setup section

On host’s side, services.prometheus.exporters = {}.
On node’s side, services.prometheus.scrapeConfigs = [].