Remember the days when everyone and their pet iguana was raving about Arch Linux? You couldn't escape the ever-so-subtle "I use Arch BTW" remarks in every Linux forum. Well, move over, Arch, because NixOS is here to steal your thunder! Nowadays, it seems that you can't browse YouTube or read a blog without stumbling upon someone extolling the virtues of NixOS and how it is the epitome of computing perfection. But hey, who needs critical analysis when we can jump on the hype train and declare NixOS as the new Arch? Because that's exactly what's going on. NixOS has now become the self-proclaimed prodigy that's poised to dethrone Arch Linux as the holy grail of Linux distributions. The time is calling, my friends! It's time for you – the seasoned Linux enthusiast – to dust off your keyboard warrior capes and embark on a new crusade. So, grab your Tux plushie (or, your pitchforks if you belong to the world of devils) and let's embark on an adventure through the enigmatic world of NixOS (and let the memes commence)!
Nix (the package manager) does not depend on systemd in any capacity; just like apt, apk or Pacman do not depend on systemd.
NixOS currently uses systemd and cannot be ported without major restructuring. So far the enthusiasm to do that has been very limited. InitWare may be the path forward but that project seems to have stalled.
Note that NixOS also does not support any kernel other than Linux either.