Puck.js ADV_IND does not contain the sensor value

I guess it's because you're just running the code once, and also you're trying to output a value between 0 and 1 as an integer?

What about:

setInterval(function() {  
  NRF.setAdvertising([
    {0x181A : [Puck.light()*100]}], 
   {interval:500}
  );
}, 500);

The example code on http://www.espruino.com/Reference#l_NRF_­setAdvertising shows how you could report the temperature using setInterval as well.