Preheat the oven to 350°F and lightly spray a 9x13-inch baking dish with nonstick spray.
In a 4-5 quart heavy bottom stock pot over medium heat, stir cream cheese until melted.
Sprinkle ranch dressing mix, onion powder, and cracked black pepper over the melted cream cheese and stir to combine. Remove from heat.
Stir in green onion, shredded chicken, crumbled bacon, and 1 cup of shredded cheddar until fully incorporated.
Place the bottom halves of the Hawaiian rolls evenly in the prepared baking dish.
Spread the chicken ranch mixture evenly over the bottom rolls.
Sprinkle the remaining 1 1/2 cups shredded cheddar cheese evenly over the chicken mixture.
Lay the top halves of the rolls over the cheese layer.
Use a pastry brush to spread melted butter evenly over the top rolls.
Sprinkle grated Parmesan cheese evenly over the buttered tops, followed by chopped fresh chives.
Cover the dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake an additional 5 to 8 minutes until the tops are golden brown.
Remove from oven and let rest for 5 minutes before slicing into individual sliders.