If I have multiple Chesnaught V with the "Needle Line" Ability in play, will each of them put 3 damage counters on the Attacking Pokemon, or does "Needle Line" only work for the Active Chesnaught V?
Each separate Needle Line Ability will stack to add 3 more damage counters to the Attacking Pokemon, but only when the Active Chesnaught V is damaged by an attack.
Source: Silver Tempest FAQ; TPCi Rules Team (2022-11-10)