Between pieces of plastic wrap or waxed paper, place each chicken breast smooth side down; gently pound with flat side of meat mallet or rolling pin until about 1/4 inch thick. In small bowl, combine 1 tablespoon chopped sage, bacon and mushrooms; divide evenly among chicken breasts, mounding in center. Roll chicken over filling, tucking in ends to enclose filling.
Spray 5-quart slow cooker with cooking spray. Place chicken roll-ups in slow cooker, seam side down. Brush tops of chicken with butter; sprinkle with salt and pepper. Pour broth around chicken.
Cover; cook on Low heat setting 3 hours to 3 hours 30 minutes.
With slotted spoon, remove chicken to serving platter; cover to keep warm. Strain cooking liquid; pour into 1-quart saucepan. Heat to boiling. Stir in flour with whisk; boil and stir 1 minute or until thickened. Remove from heat. Stir in whipping cream and 2 tablespoons chopped sage. Spoon about 2 tablespoons sauce over each chicken roll-up. Sprinkle with cheese.