This works especially well on low level characters, but would work on characters of equal level too if timed properly.
The trick is simple, initiate a duel and put Bane of Havoc on your target, at this point you can either win or /forfeit. Direct your attention to the nearest attackable NPC and cast Chaos Bolt. Even after the duel is over, Bane of Havoc will still duplicate the Chaos Bolt onto the player.