Preheat oven to 350°. Pound chicken breasts with a meat mallet to 1/2-in. thickness. Place in a greased 15x10x1-in. baking pan. Mix 1 teaspoon basil, 1 teaspoon rosemary and 1/2 teaspoon garlic salt; sprinkle over chicken. Bake, uncovered, 18-20 minutes or until a thermometer reads 165°. Cut chicken into thin strips.
Meanwhile, in a 6-qt. stockpot, cook orzo according to package directions, adding spinach during the last minute of cooking. Drain and return to pan. In a small bowl, whisk oil, mustard, oregano and remaining basil, rosemary and garlic salt; add to orzo. Add tomatoes, 1 cup Asiago cheese, feta cheese, pine nuts and chicken; toss to combine. Sprinkle with remaining Asiago cheese.