I just oredered and installed a cv axle passenger side and the ______!@#$$%% shaft nut is a different size. ok should I remove and take back shaft assembly or can I just find a new NUT???? why are they different??? Picked these up at NAPA. Does ABS make a difference on shaft nut size??? HHEEEELLLLLPPPPP! so close but so far away!

new axle did not come with a new nut?

Yes they should always come with a new nut. If it didn't, then you got a returned axle where the person neglected to return the nut most likely.