Your radio is manufactured by Clarion, and on this forum and many others, nobody as far as I can see has a serial number to radio code database for Clarion.
The other Nissan radios you see here where codes are being supplied are manufactured by Blaupunkt, where I and many others have a progam where we can
calculate the code from the serial number.
Hope I've helped answer your question. Initally I'd try the dealership , some I've heard will provide a code from your chasis number for free
providing they establish you're the owner of the vehicle, but sadly many will charge.