Oh, I didn't know this.
I've only heard "charlatán" used as you define the word in English, Poli.
But I just asked someone older than me, and they are quite comfortable with the word referring to a person that will speak non-stop or that talks nonsense. The use might be a little archaic.
I'm not really surprised though about this meaning; it has the root "charlar" (to chat or to talk nonsensically) in it. In context, I wouldn't have objected the use.
