diff --git a/installer/nixos-rebuild.sh b/installer/nixos-rebuild.sh
index c1df6e5613c6..0691f5ccfbd5 100644
--- a/installer/nixos-rebuild.sh
+++ b/installer/nixos-rebuild.sh
@@ -25,7 +25,7 @@ if test -z "$action"; then showSyntax; fi
 # Allow the location of NixOS sources and the system configuration
 # file to be overridden.
 NIXOS=${NIXOS:-/etc/nixos/nixos}
-NIXPKGS=${NIXPKG:-/etc/nixos/nixpkgs}
+NIXPKGS=${NIXPKGS:-/etc/nixos/nixpkgs}
 NIXOS_CONFIG=${NIXOS_CONFIG:-/etc/nixos/configuration.nix}