Final answer:
The most important action for a nurse to take in order to have a new nursing diagnosis considered for inclusion in the NANDA-I taxonomy is to provide evidence-based research to support nursing care.
Step-by-step explanation:
The most important action for a nurse to take in order to have a new nursing diagnosis considered for inclusion in the NANDA-I taxonomy is to provide evidence-based research to support nursing care. NANDA-I (North American Nursing Diagnosis Association International) is the organization responsible for the taxonomy of nursing diagnoses. By providing evidence-based research, the nurse can demonstrate the clinical significance and validity of the new nursing diagnosis.