MarieElla
Yes, fancyflowers, she was hated for her treatment of Katherine and known to have a violent temper, often mistreating her maids...so yes, Nan Bullen was used as an insult which was deserved.
It may have been used as a put down in the 1530s, but why use it nowadays? It's hardly a widespread name for Anne - yes, we all know of it from TV drama and historical fiction, but it's hardly in common use.
All we know about Anne (as with most historical figures) is what men wrote about her. The people doing the writing all had vested interests in discrediting her - it was necessary for her to be guilty, as she had been executed so that Henry could get an heir, and/or so that he could be rid of her when his infatuation wore off. If the writers didn't make her unpopular, so the people felt that her death was deserved, there could be an uprising.
Henry had taken great pains to ensure that the marriage was legal in the eyes of the law and the church, so there had to be good reason for him to kill her off. It is highly unlikely that she was guilty of adultery, which made the pretext for her execution all the more perilous. If Anne had been a legitimate queen, then Elizabeth was a legitimate heir.
It is fair to say that the dissolution of the Catholic church caused great unrest, particularly as those who refused to convert to Protestantism were persecuted.
There is no doubt that the political and religious changes necessary for Henry to legitimise any children Anne might have were widespread and probably unpopular, but the personality of Anne - her temper, her scheming, her witchcraft, promiscuity, extra finger and so on is all speculation. How can anyone in the 21st century know how she treated her maids? And why would the man or woman in the street care, much less the courtiers who may well have also treated servants badly.
'Nan Bullen' is a commoner name, so is the sort of thing that people like those who talk about 'Rachel from Accounts' might have used - it's basically saying 'don't get above yourself, woman'. It's bad enough copycatting modern day insults - but copying ones from the 16th century is a whole new level surely?