Hello,
Does Nuki support update firmware via the nRF Toolbox? Or does this process require Nordic chip?
No. Nuki devices have their own update mechanism which includes secured download from the server and transfer to the device. You can not download any binaries on your own nor use a tool like nrf toolbox to transfer them.
Is this true for all versions? Does it also apply to the Bluetooth version without integrated wifi chip? Is it possible to download an installation file from the server that contains the bootloader and firmware file similar to the one in the picture?
Yes, yes & no.