Final answer:
In New York State BLS protocol, nitroglycerin for chest pain should only be administered if an adult patient's blood pressure is 100 mmHg or higher to avoid the risk of hypotension.
Step-by-step explanation:
According to the New York State (NYS) Basic Life Support (BLS) protocol, the administration of nitroglycerin for chest pain is indicated if the adult patient's blood pressure (BP) is ≥100 mmHg. This means that a systolic blood pressure of at least 100 mmHg is required before considering the administration of nitroglycerin to treat chest pain, to avoid hypotension, which can be dangerous for the patient.