Preheat oven to 350°F (175°C).
In a large mixing bowl, combine softened cream cheese, dry ranch dressing mix, onion powder, black pepper, and green onions; mix well.
Stir in shredded chicken, crumbled bacon, and 1 cup of shredded cheddar cheese until evenly combined.
Spread the chicken mixture evenly over the bottom halves of the Hawaiian rolls.
Sprinkle remaining 1½ cups cheddar cheese over the chicken mixture, then place the top halves of the rolls over the filling.
In a small bowl, mix melted butter, grated parmesan cheese, and chopped fresh chives.
Brush the butter mixture generously over the tops of the assembled rolls.
Place sandwiches on a baking sheet and bake for 15-20 minutes until cheese is melted and tops are golden brown.
Remove from oven, allow to cool slightly, then serve warm.