This fight is who kills the other faster. Can Sans kill Chisaki before he gets hit once? Can Chisaki kill Sans before he gets killed by Sans' soul attacks?
I don't know much about Undertale to say if Sans could dodge Chisaki's attacks.
However I can say that Chisaki has no feats of dodging such projectile attacks.
His best dodge comes from here, nothing special at all. To be honest, from what I've seen in youtube videos, Sans first attack might just straight up kill Chisaki before he can even do anything.
I assume when Sans slams a soul to the ground in battle, that would also affect Chisaki's body as well. Which means the fight starts with him getting slammed into the ground and hit by multiple bones/blasters that attack the soul? I don't know if Chisaki can survive Sans first attack in this case.
I'm leaning towards Sans rather heavily, but I'll save my vote/thoughts for now.