Make a nixos module and make the readme suggest you use that

flake.nix

@@ -30,6 +30,27 @@
         ntv2-driver = linuxFinal.callPackage ./ntv2/driver.nix { inherit ntv2-src; };
       });
     };
+    nixosModules.default = { config, lib, pkgs, ... }: {
+      options = {
+        ntv2 = {
+          enable = lib.mkOption {
+            type = lib.types.bool;
+            default = false;
+            description = "If enabled, install the AJA driver, utilities, and gstreamer plugin.";
+          };
+        };
+      };
+      config = lib.mkIf config.ntv2.enable {
+        # Apply the overlay to the system nixpkgs
+        nixpkgs.overlays = [ self.overlays.default ];
+        # Include the kernel module...
+        boot.extraModulePackages = [ pkgs.linuxPackages.ntv2-driver ];
+        # ...and load it automatically.
+        boot.kernelModules = [ "ajantv2" ];
+        # Include the utils and demos, and the gstreamer plugin
+        environment.systemPackages = [ pkgs.ntv2 pkgs.ntv2-gst ];
+      };
+    };
   } // flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
   let
     pkgs = import nixpkgs { inherit system; overlays = [ self.overlays.default ]; };

readme.md

@@ -7,20 +7,9 @@ gstreamer plugin. This allows you to use Aja video IO cards on NixOS.
 ## Usage
 
 - Add the flake to your system flake's inputs.
-- Apply the overlay to your system's nixpkgs, e.g.
+- Enable the module by adding the following to your system config:
   ```nix
-  nixpkgs.overlays = [ ajantv2.overlays.default ];
+  ntv2.enable = true;
-  ```
-- Add the kernel driver:
-  ```nix
-  # Include the kernel module 
-  boot.extraModulePackages = [pkgs.linuxPackages.ntv2-driver];
-  # And load it automatically
-  boot.kernelModules = [ "ajantv2" ];
-  ```
-- Include the utils/demos and gstreamer plugin:
-  ```nix
-  environment.systemPackages = [pkgs.ntv2 pkgs.ntv2-gst]
   ```
 
 ## Gstreamer