Is Kai'sa statcheck?

80% of all ADCs are stat check

Yes Kai'sa is one of them, she is just a ranged Yi

If you consider stat checking champions to be champions like or or who generally just faceroll you with relatively little thinking on their part after they get fed (and im NOT saying they are "braindead" in ANY way), then I would not consider a stat check champion, mainly due to how she can be punished for going in with R and how her Q is relatively short range.

Kaisa's only decision making is when to ult. After that you just smash every ability off cooldown.