on page 183 it says that "Attacks have a special Outcome ..."
I took this to mean you use the damage and defeat rules in stead of the "outcome - difficulty" rules that can result in complications
That sounds about right...
for example during our last session one of my players was involved in an honor duel. His opponent got a pair of fours and the player got a pair of twos, they both got two nudges.
The question is, can the player use those two nudges for anything? Or should I count the pair of 4s as the difficulty and give the player two complications in addition to the reputation damage he took from the honor duel?
In this case, Nudging failure would normally be used by the loser of the roll (I assume in this case that was the character rolling his Defense dice?) to eliminate Complications. Remember, all rolls in a Conflict are either a Contest or a Challenge - since this was a head to head roll, it's a Contest and you'd use the winner's Result of 4 as the Difficulty to determine the loser's Outcome (page 160).
Fortunately, though, the loser of this round would not suffer any
Complications, because of the Nudging Failure rules (page 155) - his Outcome gives him 2 Complications but those Complications are negated by his 2 Nudges anyway