Hi, and thanks for your medical question on eHealth forum!
Brown discharge from nose can be due to chronic sinusitis, nasal polyps and picking at nose. If it is coming from mouth it can be due to a bad gastric reflux, smoking, alcohol use, gastritis, acidity, tumors of stomach and food pipe, bleeding gastric ulcer etc. If it is coming from mouth you can try omeprazole empty stomach in morning and an antacid gel at bedtime. Refrain from smoking, alcohol, fuzzy drinks and spicy food.
Since a confirmed diagnosis cannot be given on net please consult your doctor regarding this at the earliest. Hope this helps. Take care!