For those like me who have had limited exposure to MbedOS, you may be interested in this course on edX. It is provided by ARM and covers some basics about the Mbed APIs. I audited the first course as it seems the second course and professional certificate are on hold right now.
Overall, I would say that the quality of the course is not as high as the TinyML course, but I still learned quite a bit and it provides access to a simulator of an ARM chip to run code on. If you are interested in learning more about this feature of the Nano 33 BLE Sense or other chips using MbedOS it may be worth your time.