Final answer:
The nurse is using the case management nursing care delivery model to oversee the care of patients with severe diabetes and heart failure to improve cost-effectiveness and quality of care.
Step-by-step explanation:
The nursing care delivery model that the nurse is using is Case management.
Case management focuses on coordinating and managing the care of patients with complex health conditions in order to improve cost-effectiveness and quality of care. The nurse in this scenario is overseeing the care of patients with severe diabetes and heart failure, which requires coordination and collaboration with a multidisciplinary team and other healthcare providers.
In case management, the nurse acts as a central point of contact and advocate for the patients, ensuring that they receive appropriate and timely care, making referrals when necessary, and monitoring their progress and outcomes.