I believe it can go either Deidara high diff or Nardo mid-high diff.
Deidara doesn't commonly begin his fights with C3 or C4; in fact, he was nearly toying with Sasuke during their fight, flying just out of range of his attacks in order to watch. Gamabunta can possibly slice Deidara out of the sky, or toad oil bullet to affect his clay. The key to Nardo's victory is his summon, and FRS. Sensing should allow him to dodge most bombs, though now all.
If Deidara manages to launch C3 toads can possibly serve as meat shield, but Nardo really has no counter to C4. However this was Deidara's last ditch effort; if Nardo somehow manages to get out of range, perhaps via toad summon jumping, Deidara will be completely out of chakra. Then it's pretty much GG.