Replacing the 6 disk cd changer

[nctrevor24]

I have an 08 altima with the nav and bose system. Below the nav system is a separate 6 disk cd changer i want to rip that out to put a deck in with usb capability but i want to leave the nav system and i know the nav system controls the cd player now is there going to be any problems if i install the new deck? It seems like ill have almost two radios. Or even easier is there anything i can buy to attach to the back of the nav system to just have a usb port for a flash drive to play music? i really dont want to replace the entire nav system with another for 600+

Thanks