What is the nutritional value of a fingernail?

You mean, like, eating it? About the same, I would think, as eating hair.

@Jeruba Yes. What is the nutritional value of hair too?

For what it is worth, I did a Web search and found this. In summary, hair and nails are mostly made of keratin, which is difficult to digest and does not have very many calories.

Much less than the nutritional value of tree bark.

Maybe as Fibre, so negative nutritional value. But fingernails sometimes have some gunk stuck to them. Mmm mmm, gunk.

Rhino horn is also keratin. Perhaps we can sell our fingernail clippings as White Rhino Horn powder and make some $.