Here's the re sync guide. Be warned though you must have another working keyfob to begin with first. Also if the procedure fails for any reason no keyfobs will work and you'll have to go to Nissan for a full re sync.
Procedure:
First of all you must open your car with the working keyfob.
1. Turn the ignition switch from Position 0 to ON 6 times within 10 seconds.
2. Then turn ignition switch to OFF position. Leave key in ignition switch.
3. After 2 seconds, the system will enter programming mode and will flash the warning
lights twice.
4. Press and HOLD the unlock button on the Plip.
5. While pressing the unlock button, press the lock button 3 times.
6. Release the unlock button.
7. The warning lights will flash once to indicate successful programming.
8. Repeat procedure 4 to 7 for up to 4 plip key’s.
9. When completed turn ignition ON, and the warning lights will flash 2 times.
10. Remove key, and check all plip key’s for operation.
NOTE : The programming mode will stop when either the ignition is switched ON, 4 plip keys
have been programmed, or no input signal either from the switch or plip keys has been received
for 120 seconds.
