Can you clarify what you mean by "gone nuclear"? I'll admit, that's not ringing a bell in my mind when it comes to Congress, but it's also late here and I'm tired.

EDIT: Ah, rules changes on filibuster and such. There's no guarantee. The Republicans do only have 51 members, though, with 48 for the Democrats and (per CNN's results) 1 seat still being tallied (?).

They could change the filibuster rules and make it easier on themselves, but it's a much narrower margin than in 2009.

EDIT 2: Regarding the empty seat, that's LA. If people vote in the runoff (not still being tallied) by the same party lines, it'll likely go to the remaining Republican candidate. So it'll be 52/48. Rule changes will need Democrats on board with them, this is unlikely.