Neti Pot. The nose is usually running for a reason. The reason should be determined and treated. My first suggestion for self treatment, would be the use of a neti pot to flush the nose. Using distilled or boiled water with salt, it will help clean out the irritants and mucous. Saline nasal sprays will also help. For short term symptom relief, otc antihistamine/decongestant pills are available.
Runny Nose. Runny nose generally responds to antihistamines. Many are available over the counter, diphenhydramine, chlorpheniramine, brompheniramine, fexofexadine, cetirize, and loratidine are are just a few. Each varies by degree of sedation, with fexofenadine and loratidine the least likely to create any sedation, and minimal with cetirizine.
Herbal teas. Licorice and Echinacea based herbal teas work pretty good. Also, inhaling a small amount of eucalyptus oil several times during the day help. Sunshine for 30-45 min/day at noon time boosts your immunity. Alternatively, you could take a vit D3 supplement.