Final answer:
The nurse's priority action would be to request that a respiratory therapist discuss the technique for incentive spirometry with the client.
Step-by-step explanation:
The nurse's priority action when a postoperative client refuses to use the incentive spirometer following major abdominal surgery would be to request that a respiratory therapist discuss the technique for incentive spirometry with the client. This is important because incentive spirometry helps prevent complications such as atelectasis (collapse of lung tissue) and pneumonia by improving lung expansion and promoting deep breathing. By involving a respiratory therapist, the client can receive expert guidance on how to use the spirometer effectively and understand the benefits.