What's the best and simplest/easiest way to make a runny nose not so runny anymore and the inside of your nose not so stuffy anymore?

Decongestants: If you're not pregnant you could take a combination medication containing an antihistamine and decongestant for a day or two. A nasal decongestant spray can keep the nasal passages open but should only be used for a short time. Irrigation of the passages with warm salt water are safe to use for longer periods. Use a humidifier if your room is too dry.

See answer : There are both medicinal and non-medicinal ways of reducing the runny/stuffy nose. There is no "one" best way. Medicinal: otc decongestants (sprays or pills); if symptoms related to allergies: otc antihistamine. Non-medicinal: plenty of rest, fluids, nourishment; humidifier; warm compresses; warm shower or steam; saline nasal spray; peppermint, tea, ginger, chicken soup. Hope this helps.