1. Cook tortellini according to package directions; drain. Rinse with cold water; drain again. Place tortellini in a very large bowl; set aside.
2. Meanwhile, for dressing, in a screw-top jar combine the oil, vinegar, sugar, mustard, basil, pepper, and garlic. Cover and shake well.
3. Add chicken strips, chickpeas, artichokes, onion, and olives to tortellini in bowl; stir gently. Add the dressing, tossing gently to coat. Cover and chill at least 1 hour or up to 6 hours, stirring occasionally. Just before serving, gently stir in chopped tomatoes. Makes 12 servings.