COOK spaghetti as directed on package.
MEANWHILE, heat dressing in large nonstick skillet on medium-high heat. Add chicken; cook and stir 2 min. Add zucchini; cook an additional 2 min., stirring frequently. Stir in pasta sauce. Bring just to boil, stirring occasionally. Reduce heat to medium-low; simmer 5 min. or until chicken is cooked through. Add cream cheese spread; cook 1 min. or until cheese is melted and mixture is well blended, stirring occasionally.
DRAIN spaghetti; place on serving plate. Top with the chicken mixture; sprinkle with Parmesan cheese.