Heat oil in large frying pan; cook chicken in batches until cooked through.
Meanwhile place fish sauce, lime juice (and zest), sugar, garlic and chilli in a screw-top jar and shake well.
Boil, steam or microwave bok choy until tender; drain.
Add lime slices to same frying pan and cook until both sides are browned.
Divide chicken among service plates.
The original recipe states to spoon the dressing over the chicken, and top with the onion and cilantro. I prefer to add the dressing and half the onion and cilantro to the pan and deglaze the pan for a minute or two, then spoon it onto the chicken, topping with the remainder of the onion and cilantro.
Serve with bok choy, lime slices and jasmine rice.