there are 2 choices:
For a global effect, hold down multi and select parametric equaliser, and hold down chorus and select one.
For a sound only effect, go to sound edit, effect, scroll to parametric eq under sound dsp, and then there are 2 choices to add chorus, either chorus direct on the same page, or on page 2 add a programmable chorus via digital effect.
Any effect can be detail tweaked, saved in effect memory and substituted in the scroll selections instead of the preset variations.