Cut chicken into 1/2-inch pieces. In 10-inch skillet, melt butter over medium-high heat. Add chicken; cook about 3 minutes, stirring occasionally, until outsides turn white.
Stir in hot water, milk, sauce mix and uncooked rice (from Chicken Helper box). Heat to boiling, stirring occasionally.
Reduce heat. Cover; simmer 20 to 25 minutes, stirring occasionally, until rice is tender. Remove from heat; uncover. Stir in pumpkin until well mixed. Stir in black beans. Serve in bowls. Top with taco sauce and cilantro.