Hi Leo,
Yes, it is possible to use CAN peripheral for the S32K116 bootloader.
Unfortunately, there is no demo/example code for S32K1xx CAN bootloader.
You can use as reference application note for the serial bootloader AN12218:
https://www.nxp.com/docs/en/application-note/AN12218.pdf
There is an SW for the S32K148 which you can modify.
https://www.nxp.com/docs/en/application-note-software/AN12218SW.zip
I hope it helps.
Best Regards,
Diana