I'm afraid the NFC pins of the nRF52 on Bangle.js are used for other things, so you can't add NFC in the same way as on Puck.js.
However you could still add an NFC sticker - there was a discussion about it a few months ago: http://forum.espruino.com/conversations/353075
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I'm afraid the NFC pins of the nRF52 on Bangle.js are used for other things, so you can't add NFC in the same way as on Puck.js.
However you could still add an NFC sticker - there was a discussion about it a few months ago: http://forum.espruino.com/conversations/353075