Overhand Chop is an ability of the Two-Handed Fighter archetype, and a PG combined it with the feat Power Attack, making an incredible amount of damages only at level 3. My question is: can he use them in the same attack? Another question for beyond level 6: when he uses Overhand Chop he can make only one attack during his round or all his attack?
Thank you and sorry for my bad English!
Your english is fine, totally understandable. A bit of advice for futures sake it helps if you put a link to or just copy paste the relevant ability in the starting post.
As to actual answer. Yes they can do that, the two are completely separate abilities that do not interact.(outside of being related to attacking.) And no they can only use overhand chop on a single attack.(either as a standard action or as part of a charge action.)
And you are at the levels where that sort of ability is really powerful. So called sweet spot. In the first 4 levels or so martial classes that use two handed weapons tend to rather massive amounts of damage compared to NPC HP. It's nothing to worry about. The character has sacrificed some AC(by not using a shield), taken an archtype for it and spent a feat(that diminishes their ability to hit.) to increase damage with two handed weapons, so it is only natural that they would be good at it.