Per an email we received today, Nations Baseball has banned the 1st to 3rd move.
Email Details below
Major League Baseball has published their 2013 rule book within the last week and the addition of the 1st to 3rd move by the pitcher is included in the new rules. Nations Baseball will enforce this new rule and we have listed it in the Official Nations rules so that it is more visible to the coach/parent that is searching for the rule. In the Official Nations Rules, rule IX.D.2.f is the new balk rule. Please make sure that at your plate conferences before each game, that the opposing coach and umpires are all in agreement on the new balk rule. This will simply avoid potential problems during the game.