Setup Arduino IDE to support Seeed XIAO BLE (Sense), fix 'exec: "adafruit-nrfutil": executable file not found in $PATH'

To add support of Seeed XIAO BLE (Sense) to Arduino IDE:
- File > Preferences
- Add https://files.seeedstudio.com/arduino/package_seeeduino_boards_index.json to "Additional Boards Manager URLs"

Tools > Board > Boards Manager...
- Search and install "Seeed nRF52 Boards by Seeed Studio"

Select board:
- Tools > Board > Arduino Mbed OS Boards > "Seeed XIAO nRF52840 Sense"
- Select correct port

Now you can try to program and upload to your XIAO BLE (Sense).

If you run on Linux, including Raspberry Pi OS, you will be reported with error:

exec: "adafruit-nrfutil": executable file not found in $PATH
Error compiling for board Seeed XIAO nRF52840 Sense.

You have to install adafruit-nrfutil manually:

$ pip3 install --user adafruit-nrfutil

Done

ref:
~ Getting Started with XIAO BLE (Sense)
~ Adafruit Bluefruit nRF52 Feather Learning Guide > Arduino Support Setup

If you have Arduino Nano RP2040 Connect also, check Remark on "Arduino Nano RP2040 Connect" of "Arduino Mbed OS Boards" vs "Arduino Mbed OS Nano Boards".