What's the best otc medicine for nasal congestion?

Short term: Short term, a decongestant such as sudafed or afrin nasal spray will cause decongestion but caution for long term use as it will quit working.

Saline: I agree that it is better not to overuse decongestants, and they may have a rebound effect and worsen the symptoms. As long as there is no pain or bleeding, a nasal saline spray and gently blowing your nose in a tissue will help to relieve symptoms.