It could have had something to do with it, but the RC can still work in a dream even if your nose is blocked. Was your nose clogged or clear in the dream? Also you have to believe that the reality check will work while you are doing it. Don't just do it without thinking about it. You have to actually believe you will be able to breath through your nose. Even if it doesn't work, you should still look around and ask yourself if it is a dream. See if anything looks unusual. Anyway awesome job becoming lucid, and good luck with your next LD!