I had the worst nasal congestion when I was on low carb so yes (no allergies though). I would read Newsletter 3. Specifically Danny Roddy on carbon dioxide and all the links in the article.
You can also check out normalbreathing.com although imo that website is kinda messy, but probably its just my browser. I got an exercise from that website I do that quickly opens my sinuses. Normal inhale+exhale that takes 2-3 seconds then pause 2-4 seconds and repeat.