Powers such as deflecting lighting with your own hands or lightsabers is rare skills only a few Forceusers can do . In itself it is powerful to do so but not only that but to know when to do it makes you skilled at the use of it.
Revan was skilled in knowing when to do so and by doing it he turned a move ment to kill him back at its user and turn her to dust without even getting damaged by deflecting it .
Think about it , it turn Nyriss to ash by how powerful the forcelightning was. She was unable to resist her own lighting but Revan resisted it and deflected it back at her.
We can do ""WHAT IFs"" all day but the fact that Nyriss was killed in the fight because Revan deflected ""HER OWN"" Force Lightning back at her and she could not defend from it , says he won the fight .
You guys act like she told him "Hey look Revan I am gonna shoot lightning at you so powerful it will turn you to ash" and by some COSMIC STUMBLING he was able to deflect it back lol >
Sorry friends but Revan won that fight , and the fact Nyriss was beating Scourage and Surik with ease before Revan showed up says alot !
Was mace more powerful than Sidious because he deflected Sidious's lightning back at him deforming his face?
Nope, Sidious fried him then pushed him out of the window with ease. He even laughed while doing it yelling he had unlimited power while the moment before that playing weak. He wasn't even going full blast on mace, Nyriss went for a killing blow immediatly and look how that turned out.. :P