Preheat oven to 350°F and line a baking sheet with parchment paper. Set aside.

In a large skillet over medium heat, melt the butter and add the sliced onions, salt, and pepper. Cook, stirring often, for about 6-8 minutes until onions have browned and become translucent. Remove from the heat.

Use a bread knife to slice the buns in half horizontally across then place the bottom buns onto the prepared baking sheet.

In a large bowl, combine the rotisserie chicken, cooked onions, and BBQ sauce. Stir and coat the chicken in the sauce.

Spread the coated chicken and onions in an even layer over the bottom buns. Then place the top buns back on.

In a small bowl, add the butter, brown sugar, and parsley. Microwave for 10 seconds, just until melted. Stir to combine.

Brush the butter mixture evenly on top of the buns.

Tent with foil and bake for 15-20 minutes. Remove the foil and then bake for an additional 5 minutes if needed to toast the buns.

While the sliders are in the oven, prepare the coleslaw. In a bowl, combine the coleslaw mix and coleslaw dressing.

Remove the sliders from the oven, lift the top buns off and set aside, then spread the prepared coleslaw on top in an even layer. Place the buns back on top.