# In your flake.nix
{
  inputs = {
    # Your Nixpkgs input
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    # Add an input as such. Do NOT add the "follows" line (a typical flakes
    # pattern) if you intend to use the binary cache.
    nyxexprs.url = "github:notashelf/nyxexprs";
    
    # Other inputs
    # ...
  };
}

{ 
  inputs,
  ...
}: {
  # For this to be valid, you need `inputs` in the argset above and nyxexprs
  # to be in your `inputs`, as demonstrated in the flake.nix example
  environment.systemPackages = [
    # `pkgs.stdenv.hostPlatform.system` is an explicit way of replacing
    # `pkgs.system`. It is especially important on systems with aliases
    # disabled in their nixpkgs config. Nixpkgs also likes enjoying changing
    # things around every once in a while, so being explicit is good.
    inputs.nyxexprs.packages.${pkgs.stdenv.hostPlatform.system}.tempus # example
  ];
}

{
  inputs, # needs to be in scope, e.g., with `specialArgs`
  pkgs,
  ...
}: {
  nixpkgs.overlays = [inputs.nyxexprs.overlays.default];
  # Overlays modify the `pkgs` instance. If consumed, all
  # of my packages will be appended directly to your pkgs
  # at which point you can consume them as `pkgs.package`
  environment.systemPackages = [
    pkgs.tempus # example package
  ];
}

{ 
  nix.settings = {
    builders-use-substitutes = true;
    substituters = [
        # Add the Nyx cache
        "https://nyx.cachix.org"
    ];
    trusted-public-keys = [
        # And the trusted public key for Nyx
        "nyx.cachix.org-1:xH6G0MO9PrpeGe7mHBtj1WbNzmnXr7jId2mCiq6hipE="
        # Other trusted public keys
        # ...
    ];
  };
}