yes. But keep in mind:
- you need to adopt the code to use a port on the mcp23017 instead of a digitalWrite of a common pin.
- the mcp23017 is I2C. When you deal with "select pin" I assume you connect your RFID with SPI. So why don't you use an SPI Port expander like the MCP23S17?
- using a MEGA instead of an UNO is far easier for a beginner.
- Revisit your older threads - I assume most of your questions were already answered last year:
