Preheat oven to 350?F.
Slice the Hawaiian rolls in half and place the bottom halves in the bottom of a baking pan. 12 in each pan.
Sprinkle shredded chicken on each slider, add a slice of cheese if desired.
Return the top bun to each slider.
Repeat with all the remaining sliders.
In a medium bowl, combine the Dr Pepper, dijon mustard, melted butter, garlic powder, chopped grilled onions, Worcestershire sauce and soy sauce.
Drizzle the sauce over the tops of the slider buns slowly trying to get each slider covered a bit.
Sprinkle the tops of the sliders generously with poppy seeds.
Cover your pan loosely with tin foil and bake for 10-12 minutes. Remove the tin foil about 8+ minutes in.