Final answer:
The most likely occurrence in this patient is Bronchiolitis obliterans (BOS).
Step-by-step explanation:
The nurse would determine that the most likely occurrence in this patient is Bronchiolitis obliterans (BOS). Bronchiolitis obliterans is a condition characterized by inflammation and scarring of the small airways in the lungs, leading to airway obstruction. It is a common complication following lung transplantation and can cause symptoms such as exertional dyspnea, nonproductive cough, and wheezing.