Question: how long to cook a chicken breast in fan oven?
Answer: Heat the oven to 200C/fan 180C/gas 6. Tip a couple of tbsp olive oil into a small roasting tin. ... 
Roast for 20-25 mins until the chicken is cooked through – check by poking a knife into the centre of each breast to make sure the juices run clear. Rest for 5 mins before serving.