Is she doing this continously? if so I think something is seriously wrong, if you can afford it and have an avain vet close by I would suggest taking this duckling in for an examine. I can understand why she is reluctant to dunk her head she is struggling to breathe. I'm truly not tring to scare you but this is not normal and seems like it would have already worked it self out if it was something stuck in her nares. most ducklings learn pretty quick how to clean out their nares and eyes it's in their DNA.