Example of Schematic to be used, resistors (1k ?) to the adjusted midpoint (+/-) at inputs within 20 or 40 mV (scale). Depends on the joystick used (100 Ohm ?).
EDIT: these resistors are not needed if you don't care about Common Mode input voltage : min=AGND+1.2V and max=AVDD-1.3V. If used, then take same resistors from the same "lot", and "paired" if possible, and well "placed". I could use at full scale of measuring, in my case, some uV ...
Using the two inputs (A and B) let one use an x-y joystick, just mounting 2 pots in parallel.