diff --git a/nix/sources.json b/nix/sources.json
index 48ef1d16..08af6366 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -24,15 +24,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
-        "branch": "nixos-20.09",
+        "branch": "nixos-23.05",
         "description": "Nix Packages collection",
         "homepage": null,
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "1c1f5649bb9c1b0d98637c8c365228f57126f361",
-        "sha256": "0f2nvdijyxfgl5kwyb4465pppd5vkhqxddx6v40k2s0z9jfhj0xl",
+        "rev": "e11142026e2cef35ea52c9205703823df225c947",
+        "sha256": "1w5bp7vv56878g4zzykgbcvqib40dwg4fn9mxrwlg6gc8gdjimfx",
         "type": "tarball",
-        "url": "https://github.com/nixos/nixpkgs/archive/1c1f5649bb9c1b0d98637c8c365228f57126f361.tar.gz",
+        "url": "https://github.com/nixos/nixpkgs/archive/e11142026e2cef35ea52c9205703823df225c947.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }
diff --git a/shell.nix b/shell.nix
index 754dd42b..080f8216 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,11 +1,29 @@
 let
   sources = import ./nix/sources.nix;
-  pkgs = import sources.nixpkgs { overlays = [ ]; };
+
   hsPkgs = import ./default.nix;
+
+  haskellNix = import sources."haskell.nix" { };
+  nixpkgsSrc = haskellNix.sources.nixpkgs-unstable;
+  nixpkgsArgs = haskellNix.nixpkgsArgs;
+  compiler-nix-name = "ghc943";
+
+  haskell-nix = (import nixpkgsSrc nixpkgsArgs).haskell-nix;
+
+  ch-hs-imports =
+    let
+      project = haskell-nix.project {
+        src = sources.ch-hs-imports;
+        inherit compiler-nix-name;
+      };
+    in
+    project.hsPkgs.ch-hs-imports.components.exes.ch-hs-imports;
+
+  pkgs = import sources.nixpkgs { overlays = [ ]; };
 in
 hsPkgs.shellFor {
   withHoogle = false;
-  tools = { cabal = "latest"; };
+  tools = { cabal = "latest"; fourmolu = "latest"; cabal-fmt = "latest"; };
   exactDeps = false;
-  buildInputs = [ pkgs.postgresql pkgs.pythonPackages.sphinx ];
+  buildInputs = [ pkgs.nixpkgs-fmt pkgs.postgresql pkgs.treefmt ];
 }