This paper responds to the prevalent discourse on the 'lack of English proficiency' among EMI teachers in contexts where English is used as an additional language. It explores how AI-powered tools, particularly ChatGPT, enable EMI teachers in Taiwan to leverage their expertise and teach in English with more confidence. This study first describes the training of an EMI PD programme. Then it reports on the challenges and strategies, and the extended and innovative use by EMI teachers after the training. By reporting on the experiences of three EMI teachers, this study shows how collaborating with ChatGPT contributes to developing an empowered EMI teacher identity. This study fills a research gap, shedding light on the transformative potential of collaborating with ChatGPT to transform content teachers' identities into an EMI teacher identity.