Preheat oven to 350° Fahrenheit. Lightly grease baking dish with cooking spray or butter, or line baking dish with parchment paper. Place bottom halves of dinner rolls in baking dish then set dish aside.
Add shredded chicken, buffalo sauce, and ranch dressing to large bowl. Stir until ingredients are fully incorporated, with chicken thoroughly coated in buffalo sauce and ranch.
Spoon chicken mixture on top of halved rolls in baking dish, spreading chicken mixture out to evenly cover rolls.
Cover chicken mixture with shredded mozzarella, making sure cheese is added in one even layer.
Cover cheese layer with top of halves of dinner rolls.
In small bowl, whisk together melted butter, Italian seasoning, and garlic powder until ingredients are thoroughly combined. Use pastry brush to brush butter sauce over tops of rolls, or carefully drizzle butter sauce over tops of rolls as evenly as possible.
Cover baking dish with aluminum foil, then place baking dish in preheated oven. Bake sliders 10 to 15 minutes, then remove baking dish from oven. Remove and discard aluminum foil and return baking dish to oven for another 5 minutes or until rolls have lightly browned. Check sliders often and be careful not to burn rolls.
Once sliders are lightly browned and warmed through, remove baking dish from oven and transfer sliders to serving tray or plates. Separate sliders to serve if desired, or serve as one large pull-apart dish. Serve sliders warm with extra buffalo sauce, ranch dressing, hot sauce, and blue cheese crumbles if desired.