Melt butter in 10-inch nonstick skillet over medium-high heat. Add chicken; cook 1 to 2 minutes on each side or until browned.
Remove chicken from skillet. Add water, mustard, salt and pepper to skillet; stirring with wire whisk until blended. Heat to boiling. Stir in rice; return to boiling. Place chicken pieces and broccoli over rice. Reduce heat to low; cover and simmer about 10 minutes or until most of liquid is absorbed and juice of chicken is clear when center of thickest part is cut (170°F).
Sprinkle with cheese; cover and let stand 5 minutes.