BRING 2 cups water to boil in large nonstick skilllet. Stir in pasta. Reduce heat to medium; cover skillet with tight-fitting lid. Simmer 10 to 15 minutes or until pasta is tender and just a little water remains in the skillet.
STIR in VELVEETA and vegetables. Cook until VELVEETA is completely melted, stirring frequently. Remove from heat. Stir in sour cream.