Man, there’s a lot of negative comments here. Just to add a different experience: my company loves Nix, it makes it really easy to integrate new tools into the dev/build environment without needing to document which packages, configuration, … a developer needs to apply to their machine manually. There’s nothing like it, really.
There are many things like it. For example, managed operating environments where the user doesn't need to do anything (and actually can't do anything). Or disposable environments like VMs and containers. Sure, it's not the same as massaging a special pet operating system over and over, but most people that need to produce software hopped off of that bandwagon years ago. I get that companies that do functional program…
Also, there isn't anything "functional" about Nix. It's a nice sales pitch, but underneath it's just a thin layer over bash scripts and environment variables.