Spanish Rice with Chicken, Olives and Chickpea Tomato Sauce Recipe

6 tablespoons olive oil, divided 8 ounces Italian sausage, sliced into 1/2-inch thick pieces 3 pound whole chicken, broken down into 8 pieces (or 1 1/2 pounds chicken legs, thighs) Kosher salt and freshly ground black pepper 2 medium onions, finely chopped (about 2 cups) 1 large green bell pepper, …