Mirrors the AMD compatibility approach from ComfyUI-NunchakuFluxLoraStacker (PR #6 + follow-up): probe nunchaku availability, gate registration of all nunchaku-dependent nodes (QwenImage/Z-ImageTurbo LoRA), and guard runtime nunchaku imports so they raise a clear RuntimeError instead of ImportError. The nunchaku-independent Krea2 ControlNet LoRA loader and the ControlNet node stay registered on every platform.