Hi @vanpye00
The i.MX8M Nano (i.MX8MN) processor does not include a native CAN FD controller. This is why you won't find CAN FD documentation in the i.MX8MN Reference Manual.
However, you can still use CAN FD with the i.MX8MN by connecting an external CAN FD controller via SPI or PCIe, such as:
MCP2517FD (SPI-based CAN FD controller from Microchip)
TJA1044GT (CAN transceiver, used with external controllers)
Regards
Daniel