The hitch merely hides it and a thief will still know it it is there. Nissan should offer a spare tire lock of sorts that locks into the hole where the crank goes. The cable lock is cheap. Most are designed for outdoors, just check it frequently and lube it maybe even cover the lock mechanism with some tape. Glad I could help.
Here is the OEM type, though I cannot find one for a Pathy, the ones for the Frontiers may work. Talk to your local parts guy and see if they can let you try one....
http://www.courtesyparts.com/Merchan...Category_Code=