Place the chicken into a large snap-lock bag. Add half the spice mix and shake until chicken is well coated. Remove chicken and any spice in the bag to a plate and set aside for 5 minutes.
Heat a deep large frying pan over high heat until hot. Add half the oil to the hot pan and cook the chicken, in batches, for 2-3 minutes each side or until light golden. Remove to plate.
Reduce heat to medium, add the remaining oil with onion, garlic and remaining spice mix, cook, stirring often for 3 minutes until onion has softened. Add the mushrooms, cook, shaking the pan occasionally for 5 minutes until mushrooms are just tender.
Return the chicken to the pan, add the lemon, olives and 250ml of stock to pan, cover and cook over medium heat for 25-30 minutes, adding more stock if required or until chicken is cooked through.
Scatter over the almonds and serve with couscous.