Place chicken and 2 tablespoons salad dressing in small glass dish or resealable plastic bag; turn chicken to coat all sides. Cover dish or seal bag; refrigerate at least 1 hour.
Meanwhile, cook tortellini to desired doneness as directed on package. Drain; rinse with cold water.
Place chicken and salad dressing mixture in medium skillet. Cook chicken over medium-high heat until no longer pink and lightly browned; drain.
In large bowl, combine chicken, tortellini, tomatoes, capers and artichoke hearts. Add 1/3 cup dressing; toss to coat. Refrigerate at least 2 hours to blend flavors. Just before serving, add spinach leaves; toss gently.