Almost never! Hi-hats generally have such similar profiles that, if you stack either one inside the other, they mute each other completely and you just get a clang sound. You could easily try this yourself. If you stack them in their original configurations, you've got... an x-hat.
I've seen a couple folks use a hi-hat cymbal in a stack (usually like an x-hat but with a china swapped for the bottom hat) but I think it's more common to use a splash or holéd cymbal on the top in that configuration.