The numbers on the small IC are: B15AD and 93C56EN

And for completeness,

the big IC has K 29451VB200 and 9933KM11

The bar coded stripe is 7Z060KT92950161

If that small IC is indeed a EEPROM I guess there is no recourse than to let Nissan replace it so they can reprogram the new chip. That may also explain why when I called my local place for a price they said it was a restricted part. Although they didn't say what that meant.