Final answer:
The best action would be to administer a high-glucose meal to increase blood glucose levels.
Step-by-step explanation:
For a patient experiencing a hypoglycemic reaction to insulin and able to swallow, the best action by the nurse would be to administer a high-glucose meal to increase blood glucose levels. This is because insulin injections allow transport and storage of glucose to increase blood glucose levels after consuming a large or high-glucose meal. By providing the patient with a meal containing high levels of glucose, the nurse can help raise the patient's blood glucose levels to a safer range.