Biggest game tonight for the ACC is Bama vs. UNC. If UNC loses, and with neutral court games against Florida and UCLA, a loss here, followed up with losses in those games, they'll have to go something like 16-4 in ACC play to be in position for an at large. And that might not still be enough depending on who the wins are against.
Pitt and Clemson have put themselves into great position, as has Duke (a win tonight would be huge though), but after that it's tough to see anyone else making a case for an at large, outside of getting to 15/16 wins in conference.