The NXP LPC546xx series devices are flashless Cortex-M4 based IoT devices. They always boot from external memory (usually QSPI flash).
SWO for the NXP LPC546xx series devices is supported out-of-the-box.
In order to make SWO working correctly, min. J-Link software V6.86d is recommended. Previous versions are not guaranteed to work correctly with SWO.
The NXP LPC546xx MCU provides to pins that can be used for SWO:
Please refer to LPCXpresso54608 Eval.