J2Chrono supports labeling using RFID printers. With RFID printer you can print and program RFID tags automatically and simultaneously.
For tag programming see: Programming a tag for J2Chrono timekeeping purposes
Zebra printers
Zebra Programming Language (ZPL)
https://en.wikipedia.org/wiki/Zebra_Programming_Language
ZPL templates
J2Chrono supports ZPL templates with three parameters named as follows:
epcdatahex: "00000001000000000000007B" epcdatadec: "123" othertext: "123 Jason Bourne"
Zebra Designer
You can create ZPL template using ZebraDesigner 3 for Developers software.
Remember to add required variables and RFID tag programming to the template. Use ZebraDesigner to either store template to your printer directly or export template in ZPL format to save to printer manually.