The Cory Fowler library has an example of accessing two CAN networks. Did that not help?

Did you ever get this working? If so, could you please post the circuit diagram you used. I am wondering if the connections between the ESP32 and the MCP2515 CAN chip have to be voltage-level adjusted since they operate at 3.3V and 5V respectively? E.g. See "Bidirectional Logic Level Shifter Circuit...