Preheat oven to 375 degrees. Grease an 8x10 inch baking dish with butter or cooking spray. Set aside.

In a bowl, mix feta, chopped spinach, parsley, minced garlic, olive oil and 1/2 teaspoon pepper. Pound out chicken breasts so they are approximately 1/2 inch thick (or at least of equal thickness).  Scoop out an even amount of stuffing onto each chicken breast. Roll up stuffing into chicken and secure with toothpicks.  Place chicken into baking dish.  Bake for 35 minutes; until no longer pink.

While chicken bakes, cook couscous as directed on package and prepare the sauce. In a saucepan on the stove, mix tomato sauce, diced mango, salt and remaining 1/2 teaspoon pepper.  Heat over medium and bring to a boil, reduce heat and simmer for 15 minutes.  Sauce should become thick as it cooks.

Top chicken with sauce and serve with couscous and any remaining mango.