Preheat the oven to 350°F (175°C).
In a large bowl, combine the shredded rotisserie chicken, pineapple chunks, mozzarella cheese, mayonnaise, Dijon mustard, soy sauce, honey, garlic powder, and black pepper. Mix well until all ingredients are evenly coated.
Slice the Hawaiian sweet rolls in half horizontally, keeping them connected. Place the bottom half of the rolls in a greased 9x13-inch baking dish.
Spread the chicken mixture evenly over the bottom half of the rolls. Place the top half of the rolls on top.
In a small bowl, mix the melted butter and poppy seeds (if using). Brush the butter mixture over the top of the rolls.
Cover the baking dish with aluminum foil and bake for 15 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the tops are golden brown.
Let the sliders cool for a few minutes before slicing and serving.