Final answer:
The nurse violated the principle of confidentiality.
Step-by-step explanation:
The nurse in this scenario has violated the principle of confidentiality, which is one of the seven principles of health care ethics. Confidentiality requires health care professionals to keep patient information private and not disclose it without the patient's consent.
In this case, the X-ray technician witnessed the nurse diagnosing a medical problem for a patient, which breaches the patient's confidentiality. The nurse should have ensured that the patient's information was not shared with unauthorized individuals.
This violation of confidentiality can undermine patient trust and have serious consequences for the patient's privacy and well-being.