Preheat the oven to 200°C. In a small baking dish, mix together the chicken, tomatoes and pesto. Roast in the oven for 10 to 12 minutes, until the chicken is completely cooked through. Remove from the oven and leave to cool.
For the salad, bring a large pan of salted water to the boil. Throw in all the green veg, bring back to the boil and cook for 2 minutes. Drain well then spoon over the pesto and lemon juice and season with pepper. Add a drizzle of oil if you think it needs it. Once the vegetables have cooled, mix through the lettuce and top with the pesto chicken.