I found this description on-line:
How To Reset Nissan NV200 SRS Airbag Warning Light
and followed the instructions -
Turn the ignition key to position “ON” without starting the engine, If your vehicle has Smart key button, press the “Start” button twice without touching the brake pedal.
Watch the airbag light closely. It will stay on for a few secs. and then as soon as it blinks off (the start of the flashing), turn the key off instantly.
Wait for more than 3 seconds
Repeat steps 1-3 two more times until you have done the cycle three times.
Now turn the key on and watch the light. It will start blinking in a different, slower manner. This is diagnostic mode. You can watch this for a little while, no hurry.
Now turn the key off again, wait for more than 3 seconds like in step 3 again, and turn back on.
Turn the ignition off and then start the engine to verify the indicator has been reset
After 4 attempts of following the above instructions the 'blinking stopped'.