Final answer:
Spicy foods make your nose run due to compounds that stimulate the mucous membranes in your nose and sinuses, leading to increased mucus production.
Step-by-step explanation:
Spicy foods make your nose run because they contain compounds like capsaicin, found in chili peppers, or allyl isothiocyanate, in wasabi and horseradish. These compounds stimulate the mucous membranes in your nose and sinuses, triggering them to produce more mucus. This is part of the body's response to potentially harmful substances, as increased mucus production can help to flush out irritants and clear the nasal passages.