How did our ancestors on the prairie treat nasal polyps?

Just a guess. Pioneers likely could not tell the difference between nasal polyps & other forms of rhinitis as they lacked the equipment to examine the nose. Two herbs that grow on the prairie they may have found useful are urtica dioica (stinging nettle) & plantago lanceolata (narrowleaf plantain). These herbs were known to native americans. Both are used as herbs for rhinitis.
Steroids or surgery. Prednisone pills or surgery. Treatment has not really come a long way since then. Unless you are Aspirin allergic asthma / samter's traid / a combination of Aspirin allergy, sinus problems, asthma and nasal polys.