Preheat the oven to 200°C.
Cut a pocket into the chicken breast and fill with Manchego and chives.
Rub the chicken with olive oil and season with salt and pepper.
Chargrill the chicken in a hot griddle pan for two minutes on each side until browned.
Transfer chicken to the oven and roast for 15-20 minutes until cooked through.
Mix salad ingredients in a bowl, season, and place on a baking sheet.
Roast the courgettes in the oven for 12 minutes until cooked through.
Blend oil, lemon juice, and basil in a food processor until smooth and season to taste.
Serve the chicken on top of the courgettes and drizzle with the dressing.