Are Koyo and NGK brands good quality brands for replacing front and rear wheel bearings or should I stick to Nissan's own ?

Nissan uses both Koyo and NSK, so they are the same thing you'd likely get from the dealer. I assume that wasn't supposed to be NGK but NSK.

rear outer bearing #nsk B31z-16C4

rear inner bearing # nachi RLS10 T C4

These were probably replaced at one time.

You should be able to go to any bearing place and they can match them up. As far as brands, let others chime in.