Final answer:
The nurse practitioner would note 'cheilosis' in the chart of the 78-year-old male patient with skin fissures and maceration at the corners of his mouth.
Step-by-step explanation:
The 78-year-old male patient with pain in the corners of his mouth, who wears dentures, smokes, and has diabetes, has symptoms indicative of cheilosis. This condition is characterized by skin fissures and maceration at the corners of the mouth. The nurse practitioner would note in his chart 'b. Cheilosis' as this best describes the clinical presentation of the patient's symptoms.