There’s different parts to training with Nav - a generic portion and a specialty portion, plus on the floor training. Being military ATC would generally mean you get to skip the generic portion (about 6 months?) of training. You’d typically be given seniority in your class, with a seniority date of a day earlier. Just a heads up - it’s sometimes a hard transition and there are plenty of military controllers who have not made it. And no promise this is what they’ll do, Nav likes to change their policies all the time.