Whisk Balsamic Vinaigrette ingredients together or shake in a small jar or combine in a small food processor. Set aside to allow flavours to blend.
Put chicken breasts in a glass bowl. Whisk marinade ingredients together (olive oil, lemon juice, red wine vinegar, garlic, oregano, thyme, rosemary, salt and pepper) and pour over chicken. Allow to marinate in refrigerator for 45 minutes to 2 hours.
Heat oven to 400°F. Remove chicken from marinade. Bake (or grill chicken) for 20 - 25 minutes or until it reaches an internal temperature of 165°F.
Arrange greens in bowls. Top with watermelon cubes, crumbled feta, cucumber, olives and cooked sliced chicken. Drizzle with Balsamic Vinaigrette or serve on the side.