Final answer:
The priority nursing instruction for a patient with systemic sclerosis and imbalanced nutrition is to consume smaller, more frequent meals to manage gastrointestinal symptoms and enhance nutrient absorption.
Step-by-step explanation:
The most important point for the nurse to teach a patient with progressive systemic sclerosis who has a nursing diagnosis of Imbalanced nutrition: Less than body requirements is to eat smaller, more frequent meals. This approach can help manage the gastrointestinal symptoms often associated with systemic sclerosis and can also improve nutrient absorption and overall intake. It's also more comfortable for patients with decreased gastrointestinal motility, a common issue in systemic sclerosis.