Melt 1 tablespoon margarine in 5-quart stockpot over medium-high heat and cook chicken, stirring occasionally, until chicken is thoroughly cooked, about 6 minutes. Remove chicken from stockpot and set aside.
Melt remaining 1 tablespoon margarine in same stockpot and cook onion, celery and carrots, stirring occasionally, until vegetables are tender, about 5 minutes. Add water, broth and corn to stockpot and bring to a boil over high heat. Stir in Knorr® Pasta Sides™ - Chicken flavor and reduce heat to low. Simmer, stirring occasionally, until pasta is tender, about 8 minutes.
Return chicken to stockpot and heat through. Garnish with parsley and season, if desired, with salt and pepper.