If you use Spiritomb's "Ghostly Cries" attack, can you put more damage counters onto a Pokemon than it would take to Knock It out?
Yes, you can. You place all the damage counters for Ghostly Cries first, then resolve any Knock Outs from the attack.
Source: Chilling Reign FAQ; TPCi Rules Team (2021-06-17)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH6_103
SWSH6_103