M.H.
Give her something else to bite. She may be looking for oral stimulation and those little nails are just so available! When my daughter went through this (and even still deals with it from time to time), I got a whole bunch of those key chains on the rubber coil bracelets in all different colors. Remove the metal key ring and she can wear one or five, whatever she wants. When you see her biting her nails, tell her to bite her bracelets instead. This may be just her "thing" and will take a while to redirect. If it continues for ages to come, keeping sugarless gum stocked is another way to keep her mouth busy when she is old enough for it.