In a small bowl mix the ingredients for the spice rub, with the lemon zest and set aside.
Rub the chicken with about half the olive oil, and pat the spice rub all around the chicken, also inside the skin above the chicken breasts and thighs. Use the entire rub, patting it on all around the chicken.
Heat the cooker using the SAUTÉ function. Add the remaining olive oil in the base of the cooker, and place the chicken breast-side down to brown – about 5 minutes.
Turn the chicken around breast-side up and pour in the stock to the side of the chicken so as not to wash off any of the spice rub.
Close and lock the lid of the cooker and set the regulator knob to the PRESSURE position. Set to HIGH pressure at 25 minutes and press START.
When time is up, turn the cooker off to use the natural release method to release the pressure (it should take about 15-20 minutes for the pressure to come down).
Once the pressure has released, open the cooker and move the chicken to a serving dish. Pour the cooking liquid into a heat-proof cup, and set aside (or use to make gravy).
Cover with foil immediately and let rest for 5 minutes before serving.