Preheat oven to 375°F. Lightly spray a 9x13 baking dish with cooking oil.
In a large bowl, combine shredded chicken, buffalo sauce, and ranch dressing. Add half the garlic powder and onion powder. Stir until evenly coated.
Slice the Hawaiian rolls in half horizontally without separating individual rolls. Place bottom half in prepared baking dish.
Spread half the mozzarella cheese over bottom buns. Spoon buffalo chicken mixture evenly on top. Add remaining mozzarella and pepper jack cheese. Place top buns over everything.
Mix melted butter with remaining garlic powder, onion powder, and parsley. Brush generously over top buns.
Bake for 12-15 minutes until tops are golden brown and cheese is melted. Let rest 5 minutes before slicing apart.