Preheat oven to 350 degrees. Tenderize chicken slightly with mallet or fork. Place chicken in oven-safe baking dish.
Whisk together salad dressing, spices, and herbs. Pour over chicken breasts, turning breasts a couple of times. Breasts do not need to be submerged in dressing, but the dressing should fully cover the bottom of baking dish. Bake chicken 45 minutes.
Wash and dry spinach leaves in a salad spinner or between two clean dish towels. Combine with raspberries, feta, and nuts in large bowl; toss to mix.
Once chicken breasts are fully cooked, remove from oven and rest 3-5 minutes. Add small amount of dressing to the salad and toss. Arrange on plates. Slice chicken into strips and serve over salad.