I've actually done two repairs on Jackson's shitty plastic nuts in the last 2 weeks and they've been broken exactly like yours.
I've played a bunch of the new Jackson stuff and it's really good considering the price points - i'd just recommend getting a replacement nut off the bat made of either graphtech or bone.
Yeah, I dunno WTF is up with that, but I've seen a bunch of them broken in stores, too. Sounds like the factory needs to change suppliers.