README: add Nix section

README.md

@@ -12,6 +12,45 @@ This repo houses official plugins for Hyprland.
  - csgo-vulkan-fix -> fixes custom resolutions on CS:GO with `-vulkan`
  - hyprbars -> adds title bars to windows
 
+# Nix
+
+To use these plugins, it's recommended that you are already using the
+[Hyprland flake](https://github.com/hyprwm/Hyprland).
+First, add this flake to your inputs:
+
+```nix
+inputs = {
+  # ...
+  hyprland.url = "github:hyprwm/Hyprland";
+  hyprland-plugins = {
+    url = "github:hyprwm/hyprland-plugins";
+    inputs.hyprland.follows = "hyprland";
+  };
+
+  # ...
+};
+```
+
+The `inputs.hyprland.follows` guarantees the plugins will always be built using
+your locked Hyprland version, thus you will never get version mismatches that
+lead to errors.
+
+After that's done, you can use the plugins with the Home Manager module like
+this:
+
+```nix
+{inputs, pkgs, ...}: {
+  wayland.windowManager.hyprland = {
+    enable = true;
+    # ...
+    plugins = [
+      inputs.hyprland-plugins.packages.${pkgs.system}.hyprbars
+      # ...
+    ];
+  };
+}
+```
+
 # Contributing
 
 Feel free to open issues and MRs with fixes.