Add hyprlux to your flake inputs:

inputs = {
  hyprlux = {
    url = "github:amadejkastelic/Hyprlux";
  };
};

Then import either the home manager module or nixos module:

imports = [
  inputs.hyprlux.nixosModules.default
];

imports = [
  inputs.hyprlux.homeManagerModules.default
];

And configure it:

{inputs, ...}: {
  programs.hyprlux = {
    enable = true;

    systemd = {
      enable = true;
      target = "hyprland-session.target";
    };

    night_light = {
      enabled = true;
      # Manual sunset and sunrise
      start_time = "22:00";
      end_time = "06:00";
      # Automatic sunset and sunrise
      latitude = 46.056946;
      longitude = 14.505751;
      temperature = 3500;
    };

    vibrance_configs = [
      {
        window_class = "steam_app_1172470";
        window_title = "Apex Legends";
        strength = 100;
      }
      {
        window_class = "cs2";
        window_title = "";
        strength = 100;
      }
    ];
  };
}

Install using your favorite AUR helper:

paru -S hyprlux