**Prepare the Filling**
- In a large mixing bowl, combine the shredded chicken, cream cheese, cheddar cheese, bacon, ranch seasoning, and green onions (if using). Mix until well combined.
**Assemble the Sliders**
- Preheat your oven to 350°F (175°C).
- Slice the slider buns in half horizontally (keeping the tops and bottoms intact).
- Place the bottom halves of the buns in a greased 9x13-inch baking dish.
- Spread the chicken mixture evenly over the bun bottoms, then place the tops of the buns over the filling.
**Make the Butter Topping**
- In a small saucepan or microwave-safe bowl, melt the butter. Stir in garlic powder, parsley, and poppy seeds (if using).
**Bake the Sliders**
- Brush the butter mixture generously over the tops of the buns.
- Cover the dish with foil and bake for 15 minutes.
- Remove the foil and bake for an additional 5-7 minutes, or until the tops are golden brown.
**Serve**
- Remove the sliders from the oven, let cool slightly, and serve warm.