First off - 12in twist means that the bullet makes 1 revolution for every 12" of travel down the barrel. Older 223's have 1 - 12" twists, the newer ones should be 1 - 9" twist rate. Although I have not tried any 60 grain Nosler bullets, I am confident they will stabilize in your rifle, be it a 12 or 9" twist. You will have to try them to see if they will perform up to your expectations. Remember, every rifle is different so they like different bullets, powder, primers, cases and many other factors...just try them.
Good Luck and Good Shooting