BetterNick

    Player p = (Player) sender;

     //returns a boolean which shows if player is nicked
     BetterNick.isNicked(p.getUniqueId().toString());
   
     //returns the real name of a nicked player
     BetterNick.getRealName(p.getUniqueId().toString());
   
     //change the name and skin to the original property
     BetterNick.remove(p);
   
     //change the nick of a player
     BetterNick.setNick(p, "GommeHD");
     try {
       //set a nick of a player
       BetterNick.setSkin(p, "_korex");
     
       //set the normal steve skin to a player
       BetterNick.removeSkin(p);
     } catch (Exception e) {
       //will execute if you fetch a skin to often or if the mojang servers are down
     }