Heat the oven to 200C/fan 180C/gas 6. Season the chicken breasts all over and chill for 15 minutes. Remove the chicken from the fridge, put onto a baking-paper-lined tray, spray with a little oil and roast for 5 minutes. Add the green beans and baby corn to the tray, tossing well and roasting for another 10 minutes until the chicken is just cooked through. Cover loosely with foil and rest for 10 minutes.