Not being a very good artist, you'll have to cut me a little slack.
Anyway, the nose is contacting the back of the cock feather that you can't see, that is pointing at a 90 degree angle away from the bow. It is behind the arrow shaft, in my sketch. The feather you can see is one of the hen feathers. The nice thing about a shield cut is that it seems designed to fit the shape of a nose (some noses, anyway). If you get your nose too close to the quill, you'll hit it with the bowstring. If it is too far out on the feather, your eye won't be over the arrow.