when i played with the Nav the setup was -
Left port ( ... ) controller
Mid port ( .. ) Mouse
Right port ( . ) Nav
not sure if anything has changed since then but if the nav works when using the ps4 ports then not sure why it wouldn't work. is the nav able to keep a wireless connection with the ps4 without xim? if yes then make sure the nav is fully charged, you have the latest xim firmware.. and obviously when connecting with the xim make sure nav is OFF and connected to right port ( . ) then connect xim. make sure it is a ps3 cable too for wired or wireless connections.