Final answer:
The principle that encourages a nurse to monitor a patient's response to a pain management plan is the principle of beneficence, which emphasizes acting for the good of the patient.
Step-by-step explanation:
When a nurse assesses a patient for pain and offers a plan to manage it, the principle that is used to encourage the nurse to monitor the patient's response to the pain management plan is the principle of beneficence. This principle states that healthcare providers should act in ways that benefit the patient and contribute to their well-being. By monitoring the patient's response, the nurse is ensuring that the care provided is effectively addressing the patient's pain, which aligns with the goal of beneficence to promote the good of the patient. Additionally, the nurse's actions also can fall under the principle of nonmaleficence when ensuring that the pain management plan does not cause any unnecessary harm.