Do enlightened people "know" what nirvana is like?

Do enlightened people "know" what nirvana is like? Obviously, they can't express it to anyone else, so the question isn't super helpful. I just wondered whether nirvana is a thing that we can know as well as experience or taste. One response, one I don't (personally) want to hear about (at least without some in depth quotation) is that nirvana isn't "like" anything. And, of course, nirvana isn't similar to anything. I'm asking whether Buddhas of any sort "know" the qualities (e.g. bliss) of nirvana.