It is possible there is a cleft between mouth and nose causing the leaking of milk up into the nose area while nursing.
You can read about clefts here
http://www.petpeoplesplace.com/resources/articles/cats/52-hand-rearing-kittens-cleft-palate.htm
Another possibility is over feeding is causing reflux up through the nose.
The risk of fluids in the nasal area is that the kitten will inhale the fluids causing deadly aspiration pneumonia.
If this is a cleft problem your vet can show you how to tube feed until the kitten is old enough for surgery.
If its over feeding smaller meals may work.
Hope this helps you!
Cat Health, Behavior, Care Expert
30+ years cat owner, rescue, breeding, study of behavior & health care
Just added this and don't want you to miss it on clefts