"Understandably, since Ice Nubbins are new and can currently be found only in one hub, for the next little while Ice is harder to come by than it will be in the long run."
But as is the case with the release of anything new, give it time and things sink to a state of normality. If you really need it for cocktails or the like, then I think it's better at this point to harvest what you can. I would avoid buying it in towers/auctions for at least a couple of days 'til the price settles and even then - once nubbins become more common (assuming we get more regions with them), they'll be a dime a dozen. So in sum: very likely to be completely temporary.