diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8031ffaf..519708f9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -10,7 +10,6 @@ jobs:
       matrix:
         os: [ubuntu-18.04, macos-latest]
         nixPath:
-          -
           - nixpkgs=channel:nixos-unstable
           - nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz
 
diff --git a/action.yml b/action.yml
index e1781981..1e558caf 100644
--- a/action.yml
+++ b/action.yml
@@ -4,7 +4,7 @@ author: 'Domen Kožar'
 inputs:
   NIX_PATH:
     description: 'Set NIX_PATH environment variable'
-    required: false
+    required: true
 branding:
   color: 'blue'
   icon: 'sun'
diff --git a/lib/install-nix.sh b/lib/install-nix.sh
index 23756e65..a3b1322c 100755
--- a/lib/install-nix.sh
+++ b/lib/install-nix.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-nixPath="${1:-/nix/var/nix/profiles/per-user/root/channels}"
+nixPath="${1}"
 
 export here=$(dirname "${BASH_SOURCE[0]}")
 
@@ -28,6 +28,9 @@ nixConf
 # Needed due to multi-user being too defensive
 export ALLOW_PREEXISTING_INSTALLATION=1
 
+# Disable installation of default channel
+export NIX_INSTALLER_NO_CHANNEL_ADD=1
+
 sh <(curl -L https://nixos.org/nix/install) --daemon
 
 # write nix.conf again as installation overwrites it
diff --git a/lib/main.js b/lib/main.js
index 7f74cf4e..54943e55 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -26,6 +26,6 @@ function awaitSocket() {
         });
     });
 }
-child_process_1.execFileSync(`${__dirname}/install-nix.sh`, [core_1.getInput('NIX_PATH')], { stdio: 'inherit' });
+child_process_1.execFileSync(`${__dirname}/install-nix.sh`, [core_1.getInput('NIX_PATH', { required: true })], { stdio: 'inherit' });
 // nc doesn't work correctly on macOS :(
 awaitSocket();
diff --git a/src/main.ts b/src/main.ts
index 82ff3ea4..d3d54b4f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -15,7 +15,7 @@ async function awaitSocket() {
   });
 }
 
-execFileSync(`${__dirname}/install-nix.sh`, [getInput('NIX_PATH')], { stdio: 'inherit' });
+execFileSync(`${__dirname}/install-nix.sh`, [getInput('NIX_PATH', { required: true })], { stdio: 'inherit' });
 
 // nc doesn't work correctly on macOS :(
 awaitSocket();
\ No newline at end of file