I haven't ever heard "no sé nada" used to mean I don't taste anything.
I would say "no sabe a nada" or maybe even "no saboreo nada."
If you cannot taste something, would you say "No puedo saberlo" or "No puedo saborearlo"? Also from what I've seen, saber (to taste) is not normally conjugated in the first person.
So.. how do YOU use saber (to taste)?