Does the usb-chicklet work when your robot is programmed with the default code?
Yes.
The chicklet just makes a USB joystick look like the oldschool gameport sticks.
even though we are using a XBOX360 controller?
Yes. All the USB Chicklet does is map your controller’s axes and buttons to the appropriate variables (p1_x, p1_y, p1_wheel, p1_aux, p1_sw_top, etc.).
Only time it gets odd is if you’ve picked a configuration setting such that you’re using more than 4 buttons, in which case you’ll need to write code to check if the most significant bits of p1_wheel and/or p1_aux are set, since this is how the chicklet encodes the higher-numbered buttons.