I have a Nucleo-F767ZI board which is running the SUIT update example application. In the Readme.md file, there is a method to connect the device behind a border router, but I’m not sure how to connect the two boards. Is there a way I can connect the Nucleo board to an ESP32 running the gnrc border router example using normal jumper wires through UART?
Yes but you won’t need a border router, just a regular router will do.
You can use either SLIP or ethos to connect two boards via a serial connection. SLIP is preferred as it has less overhead (no ethernet header needed) - use the slipdev_l2addr module so SLAAC will just work.
As to how to change the border router example to be a regular router, see this thread.