Preheat oven to 375 degrees. Spray pan with cooking spray and then place chicken in pan.
Combine mayo, Greek yogurt, and buffalo sauce in small bowl. Spread mixture over chicken.
In a separate bowl, combine Panko crumbs, cheese, and Hidden Valley Ranch seasoning. Mix well. Sprinkle over chicken.
Bake in over for 45 minutes or until chicken is cooked through and topping is browned.