"用荨麻刺" can be translated as "to sting with nettles" or "prick with nettles" in English, depending on the context. If you're emphasizing the action of using nettles to cause a stinging sensation, "to sting with nettles" would be more appropriate. If you're focusing on the physical act of poking or pricking with nettles, "prick with nettles" could be used.