Set the oven to 180°C, air circulation, and rack set to the middle position.
Place the chicken fillets in an oven proof dish, season with half the salt and pepper and drizzle over them the olive oil. Place in the oven and cook for about 35' until the chicken is just cooked. Take out of the oven, allow to cool and dice the chicken into small bite-size pieces. Add to a large bowl and keep aside covered with foil.
Take the bowl of a food processor with the metal blade attached and add the mayonnaise and yoghurt along with the curry, chutney, lime juice, vinegar, dry coriander and the remaining of the salt and pepper. Blitz-pulse for a minute or so until the sauce has been well combined.
To put everything together, add into the bowl with the chicken bits the chopped scallions and celery. Pour the sauce and mix well. Fold in the apple and coriander and place in the refrigerator for 1 hour. Serve with rice at room temperature while adding on top the cashew nuts and some coriander leaves on the side.