Competency-based medical education (CBME) has become increasingly prominent in efforts to reform medical education. This approach integrates core competencies into a framework for training and evaluation, known as entrustable professional activities (EPAs), and is gaining traction in Taiwan. A foundational step in this approach is the establishment of a framework of profession-specific core competencies. This project used consensus methodology and the nominal group technique (NGT) to establish sub-competencies for dietitians in teaching hospitals. A CBME taskforce, composed of clinical dietitian instructors (n = 30) from teaching hospitals nationwide, employed the NGT to reach consensus on a 15-item framework for the sub-competencies of dietitians and on the descriptions of these competencies. The project also developed an EPA–sub-competency matrix corresponding to the seven major EPAs for entry-level dietitians (http://www.dietitians.org.tw/program/view/17). A questionnaire based on a 5-point Likert scale revealed that 86% (26/30) of participants strongly agreed that “after consensus on the core and sub-competencies is achieved, EPAs are more effective in cultivating a professional identity.” This project is the first to propose a competency framework and corresponding EPA–sub-competency matrix for entry-level dietitians in teaching hospitals in Taiwan, attesting to the beneficial role of the consensus process in fostering professional identity.