From what I heard, the Hacker gets all three powers: Change a nomination, choose a player to play for veto AND nullify a vote. This will last for two weeks and is an insane amount of power for any player.
Potentially if true, if any of the Hive players can win this they can renom someone in L4, win veto to keep noms the same and nullify a vote and possibly get an L4 person out of the house on Angela's HOH.