Mediterranean Chicken

Name: Mediterranean Chicken
Ingredients: 6 tablespoons olive oil, divided; 8 skinless boneless chicken breast halves (about 2 1/2 pounds); 1 1/2 pounds assorted wild mushrooms (such as oyster, crimini, and stemmed shiitake), sliced; 1 1/2 cups low-salt chicken broth; 2/3 cup pitted Kalamata olives; 3 plum tomatoes, seeded, diced; 3 garlic cloves, minced; 1 tablespoon chopped shallot; 1 tablespoon drained capers; 2 tablespoons (1/4 stick) chilled butter; 1 cup teardrop tomatoes (red and yellow); 3 tablespoons chopped fresh parsley; 3 tablespoons pine nuts, toasted; Caper berries, halved (optional)