Pi Pico and Zephyr RTOS

Has anyone used the Zephyr RTOS on a Pi Pico or any other smallish system?
I'm writing something relatively simple for a Pico in C using the SDK. It doesn't need an RTOS, the old classic cyclic executive paradigm will work fine.
At one time I'd have used an 8bit CPU but why faff about when you can get something like a Pico for hardly any cost even if 2x Cortex M0+ seems overkill.