Cook and stir chicken in large skillet sprayed with cooking spray on medium-high heat 5 min. or until no longer pink.
Stir in water. Bring to boil. Add pasta; stir. Cover; simmer on medium-low heat 10 min. or until pasta is tender.
Add remaining ingredients; stir. Cook, covered, 5 to 7 min. or until VELVEETA is completely melted and vegetables are crisp-tender, stirring frequently.