it'll be ok to drive, but try to get it fixed...
you'll have to cut that nut off if you can't mechanically remove it... maybe try some big visegrips clamped on with steady outward pressure to maybe catch an outward thread and get it off one last time...
you'll have to pull the rotor to put a new stud in... easy enough, but probably a couple hr's work if you've never done it...
It's an acorn nut...not going to be pleasant...
I've had the fronts off once to replace the wheel bearings...but that was before NTB screwed it up...if I remember right, the rotor and hub are one big assembly...the thing that sucks is the castle nut and keepers in there that are a PITA to put back



