Maybe choose it if your embedded board, system on a chip, or CPU is supported. NuttX has a lot of supported boards, SoCs, and CPUs, and they differ from Zephyr's supported hardware.

[1] NuttX supported platforms: https://nuttx.apache.org/docs/latest/platforms/index.html

[2] Zephyr supported platforms: https://docs.zephyrproject.org/3.2.0/boards/index.html