my bad, I recall your first message and missed the opportunity to answer.
The CFX has support for the NXP PN532 chip to read NFC, wired in I2C, like this board. It can work along with the OLED display on the same bus.PN532 NFC/RFID controller breakout board [v1.6] ID: 364 - .95 : Adafruit
The issue is that currently, I didn't have time to write a dynamic / configurable ID system for this. Not difficult, but I just did that for the demo. I look forward implementing saber lock/unlock and messages (OLED / UI sounds) like in the demo. I only have 2 hardwired IDs in the code right now, it just needs to be made dynamic in a config file (like specials.txt)
The current fw *does* print out a successful read of NFC tag though, so if you hook a reader to it, you should be able to see it in the logs (use slow boot, it's at the very beginning of the logs, along with detecting the OLED), then perform reading with tags and see it in the serial console
 currently it doesn't work along with the display (changes needed)
I'll try to tackle this again, I have to finalize the new batch of thermal detonators and sonics, plus a freelance work for a designer before I can have again saber time. Doing all those things this week to free up some time for next week.