You should get it on a scanner and read which wheel sensor/abs is not reading or reading incorrectly and fix the culprit.
I just ran into a bad connector and wire itself and had to fix on the front left wheel.
Another good practice is to change your trasnfercase fluid every other season or every season w/ appropriate ATF, the two changes I have done on mine they both came out dark and the transfercase switched from 2wd/4x4 and in and out a lot quicker,
In emergency situations I have read you can pull the ABS fuse to fool the TCCU into letting the truck into 4x4.
A bad wheel sensor will most defiantly cause it not to go into 4x4
All good advice.
Keep in mind, Nissan calls for ATF changes every 30 kmi and for differentials and transfer case, fluid change every 20 kmi, referencing what the Service Manual calls "Severe Service:"
• Repeated short trips of less than 5 miles (8 km).
• Repeated short trips of less than 10 miles (16 km) with outside temperatures remaining below freezing.
• Operating in hot weather in stop-and-go “rush hour” traffic.
• Extensive idling and/or low speed driving for long distances, such as police, taxi or door-to-door delivery use.
• Driving in dusty conditions.
• Driving on rough, muddy, or salt spread roads.
• Towing a trailer, using a camper or a car-top carrier.
The last three probably get all of us...
I didn't remember the very much shortened interval for diffs and transfer case until I was looking up something else in the Service Manual.