Getting nix-path issue when installing nixos via archlinux

Help
1

i am doing a partition install of Nixos with archlinux acting as the Host OS.

i have enabled nix-daemon, added my user to nix-users, created a nixbld user and added to the nixbld group. i installed nix via the official archlinux package.

for channels i have added nixos-25.05 to the channels under the alias of nixos and ran nix-channel --update. doing nix-channel --list gives:

nixos https://nixos.org/channels/nixos-25.05

at the step in the manual when installing nixos to the mounted partition running ‘sudo PATH=“$PATH” which nixos-install --root /mnt’ give me:

error: file 'nixpkgs/nixos' was not found in the Nix search path (add it using $NIX_PATH or -I)

so i am wondering should i create the $NIX_PATH as reading the issue linked in the archwiki it seems to cause issues?

2

Name the channel nixpkgs, or add an entry in NIX_PATH redirecting nixpkgs to nixos: NIX_PATH="nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos:$NIX_PATH"

That entry exists by default on nixos systems, so you may see examples some places that assume it exists.

3

added the channel under the alias nixpkgs did not work still getting the same issue

4

Did you run nix-channel --update afterwards?

5

yes i ran nix-channel --update.

6

Can you printenv NIX_PATH and post it here?

7

typing echo $NIX_PATH prints nothing

8

Oh, you just installed the nix package, right? Try starting a new shell, and check the variable again.

9

no i installed the nix package a while ago over several reboots as i had a bit of difficulty getting things setup for the nixos partition. just tried reinstalling the nix package and still nothing under $NIX_PATH

10

Hmm… there’s also a nix-path option that can be set in /etc/nix/nix.conf. If the env var is unset, that’s used. Is it there?

11

that file only lists build-users-group = nixbld

12

Then the arch package is not reasonably built. Which lines up with what I’ve heard secondhand. The general consensus I hear from the nix community is that you just shouldn’t use it.

That said, you can probably power through this by setting NIX_PATH manually. The channels are in /nix/var/nix/profiles/per-user/*/channels somewhere (depending on which user you ran nix-channel as).

13

alright, i will keep this in mind, i am going to try to install nix via the official script since i haven’t used it much except installing the nixos-install-tools