Why wont my drivers side door unlock with the key?

Could be your driver door lock mechanism that is going bad , since the other door are working, it cannot be the fob. I would try to change the driver side door latch mechanism.

The locks on your vehicle are electronically controlled by the BCM - body control module . The driver an passenger door switche's are input's to the BCM . Do you know anything about automotive electronic's ? anti theft alarm remote, could this be part of the problem , No it's just a key less entry remote , nothing to do with the anti-theft .
Door Lock System Components
The Power Door Lock System consists of the following components:
• Body control module (BCM)
• Driver door lock switch
• Front passenger door lock switch
• Door lock actuators in each of the doors
• IBCM (PWR) 15-amp fuse

Door Lock System Controls
The Power Door Lock System is controlled by the body control module (BCM) and can be activated by any one of the following:
• A door lock switch Lock or Unlock actuation
• A keyless entry transmitter actuation
• An automatic door lock actuation
• An automatic door unlock actuation
• A last door closed locking (LDCL) actuation

Driver and Passenger Door Unlock Operation w/o Keyless Entry
When the body control module (BCM) detects a transition of either of the door lock switches to the Unlock position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the driver passenger door lock actuators transition to the Unlock position.

Your best bet , take your vehicle to a qualified repair shop ! Need special tool to diagnose .

Power Door Locks Inoperative

Install a scan tool.
Turn ON the ignition, with the engine OFF.
With a scan tool, observe the door lock switch parameter in the Doors data list.
Does the scan tool display Idle?
YES - Go to Step 4
NO - Go to Step 8
4
Activate the driver door lock switch to the LOCK and UNLOCK positions.
Does the scan tool display Idle?
YES - Go to Step 9
NO - Go to Step 5
5
Activate the front passenger door lock switch to the LOCK and UNLOCK positions.
Does the scan tool display Idle?
YES - Go to Step 9
NO - Go to Step 6
6
With a scan tool, observe the driver door lock actuator command and the passenger door lock actuator command parameters in the Doors data list.
Activate a door lock switch to the LOCK and UNLOCK positions.

faulty master switch ..replace

looks like car has other issues as well.. but try that first

door lock actuator might be faulty or bad electrical contact
take off the door panel and diconnect and reconnect the wiring, you might need to change door lock actuator

will your key work in the passengers side?
If so I asume you have electric door locks. open drivers door from inside shut the passengers door. go around to the drivers side shut the door lock the doors from inside then unlock the doors open door shut door and try to start it...as far as disableing it you will have to take it to nissan electrical tec.

ok the switch on the drivers side not working is the problem,its not allowing the cicuit to be completed.you may want to check the passenger side lock actuator.

you have to change your lock system in the driver side. it is gone.

turn drivers side 2 times to right should unlock hole truck