It may be more a bother than anything serious, but hopefully won’t occlude the nostril. Having dogs and cats, I have seen plenty of engorged ticks. They appear bluish or very pale, and are very soft/squishy. Oddly enough we have seen some defects of the nostrils here on BYC.
Does it feel like tissue or skin? I am no expert, but maybe it is a growth from inside the nostril. How does the other side look? Have you looked up into the roof of the beak with a light for any thing odd, or yellow material? The choanal slit in the roof is connected to the sinus cavity.