Including outside flakes in home-manager

I have attempted to include the nixpkgs-wayland in a stand-alone home-manager flake like this:

{
  description                              = "A descriptive description";

  inputs = {
    home-manager.url                       = "github:nix-community/home-manager";
    home-manager.inputs.nixpkgs.follows    = "nixpkgs";
    nixpkgs.url                            = "github:nixos/nixpkgs/nixos-unstable";
    nixpkgs-wayland.url                    = "github:nix-community/nixpkgs-wayland";
    nixpkgs-wayland.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { home-manager, nixpkgs, nixpkgs-wayland, ... }:
    let
      pkgs                                 = nixpkgs.legacyPackages.${system};
      pkgs-wayland                         = nixpkgs-wayland.packages.${system};
      system                               = "x86_64-linux";
    in {
      homeConfigurations."thisusername@thishostname" = home-manager.lib.homeManagerConfiguration {
        inherit pkgs;
        inherit pkgs-wayland;
        modules                            = [ ./thishostname.nix ];
        extraSpecialArgs                   = { hostName = "thishostname"; };
      };
    };
}

This produces the following error:
error: function 'homeManagerConfiguration' called with unexpected argument 'pkgs-wayland'

Is it possible to include external flakes in a STAND-ALONE home-manager flake?
If so, where am I going wrong?

You need to use extraSpecialArgs:

homeManagerConfiguration = {
  …
  extraSpecialArgs = {
    inherit nixpkgs wayland;
  }
  …
}

Either I am dramatically misunderstanding what you intended or there are some small but significant issues in this answer.

I do not trust my own understanding though as I have been struggling horrifically through nix/nixos and feeling stupider with each passing month. I am not being a pedantic jerk; I am genuinely unsure of the answer to this question:

Is there a missing “-” and “nixpkgs” was supposed to be “pkgs” in your code block above?

Should that have been,

homeManagerConfiguration = {
  …
  extraSpecialArgs = {
    inherit pkgs-wayland;
  }
  …
}

It looks like half of my above guesswork was correct and half was incorrect. It appears that the hyphen was indeed missing but that “nixpkgs” (as @nikolo originally posted) was correct:

This seems to work as intended:

homeManagerConfiguration = {
  …
  extraSpecialArgs = {
    inherit nixpkgs-wayland;
  }
  …
}

@nikolo If you would make the small edit to add the hyphen to your original answer, I will gladly “solution”-mark your post.