I'm not too sure this was an easy out for shorts. NRF was already heavily shorted weeks ago when it was under $8.
According to NASDAQ::
No doubt that there was short covering after the dividend announcement and the fantastic earnings, but I think there are still plenty of underwater shorts out there. I don't subscribe to things that give be more up-do-date data, but I would not be surprised to still see 10 million short. I guess we'll catch them later. LOL