Install Seeed nRF52 Boards on Arduino IDE 1.8.19 to program XIAO nRF52840 Sense in Arduino Framework (on Raspberry Pi OS)

To program Seeed Studio XIAO nRF52840 Sense in Arduino Framework, we have to install "Seeed nRF Boards" and/or "Seeed nRF52 mbed-enabled Boards" in Arduino IDE.

This video show steps to install Seeed nRF52 Boards on Arduino IDE 1.8.19 (on Raspberry Pi OS 32-bit buster).

Click File in Arduino IDE MENU > Preferences
add the follow link in Additional Boards Manager URLs box.
https://files.seeedstudio.com/arduino/package_seeeduino_boards_index.json

If you are reported error of:
exec: "adafruit-nrfutil": executable file not found in $PATH

You have to install adafruit-nrfutil, enter the command in terminal:

$ pip3 install --user adafruit-nrfutil

In my case, adafruit-nrfutil installed successfully but not on PATH.

To add the installed directory to PATH, edit ~/.bashrc:

$ nano ~/.bashrc

Add following code in the end of .bashrc:

PATH=${PATH}:<installed directory>
export PATH

In nano, Ctrl-X and answer Y and ENTER to accept the file name to save and exit.

Reboot and run Arduino IDE again. DONE.

Remark:
If you cannot see your Xiao nRF52840 in Arduino IDE Port selection, double click on the onboard RST button to enter bootloader mode.

next:
~ XIAO nRF52840 Sense/XIAO Expansion board display on OLED in Arduino framework, using U8g2 Library.
~ BLE UART Peripheral run on XIAO nRF52840 Sense (in Arduino Framework)