When it comes down to powers, Chisaki can do everything Scar can but better. Deconstruction is the same between them, though either touching the other isn't going to happen. Chisaki doesn't like touching people unless he has too, while Scar will try to approach, Chisaki won't let him near by destroying the ground and attacking with spikes.
This is a range fight and Chisaki is far superior at this. Scar has only recently gotten the ability to reconstruct, while Chisaki could do it since he was 4 years old. He has far more experience with reconstructing and isn't a Glass Cannon. He can survive ranged attacks from Scar and heal any damage he takes, it also restores his stamina as well.
Scar cannot heal himself and will die in one hit. Either he keeps avoiding Chisaki's attacks until he tires out, or Chisaki hits him once before that. I don't see Scar getting close enough to touch him while he's destroying the ground.