nixos-rebuild switch does not require a reboot. In fact, you'd typically use nixos-rebuild boot if you don't want immediate changes. For very complicated recon

nixos-rebuild switch does not require a reboot. In fact, you'd typically use nixos-rebuild boot if you don't want immediate changes. For very complicated reconfigurations, it might be advisable to reboot if that involves changes to services that are only started during boot time. But that's the case for nearly any OS...