HEAT oil in large nonstick skillet on medium-high heat. Add steak and onions; cook and stir 4 min. or until steak is no longer pink.
STIR in water and broth. Bring to boil. Add noodles; return to boil. Reduce heat to medium-low; cook 7 min. or until noodles are tender, stirring frequently.
ADD Velveeta and beans; cook until Velveeta is completely melted and mixture is well blended, stirring frequently. Stir in sour cream just before serving.