Hi there,
So you can see it with Nrf_connect for Mobile then You should be able to see it with the Xiao. What code are you using? The basic BLE scanner should yield the MAC address advertising once the device it turned on.
it may time out so, be aware. If it’s a peripheral it’s services should be subscribable for the NOTIFY it sends every 30 Seconds or unless the temps change over a certain Delta (from the product description page)
Which BSP & LIB’s are you using on Xiao mbed or non. ?
Arduino BLE or Blufruit?
HTH
GL 
PJ 
What’s the end goal here?
use the code tags above " </> " paste it in there. we can get you going 