Spray or lightly butter a 7x11” or 9x13” rimmed baking sheet with softened butter, and preheat the oven to 350°F/180°C.
Season the chicken with salt, black pepper, and chili powder.
In a skillet, heat 1 tablespoon olive oil and sear the seasoned chicken on both sides, then transfer it into the oven to bake for 15 minutes or until the thickest part of the chicken reaches 165°F/74°C. Remove from the oven (don’t switch it off), and let the chicken rest for 5 minutes then shred it with two forks. Place the shredded chicken in a bowl and set aside.
In the same skillet, heat the remaining olive oil and saute the onions until translucent, about 3 minutes. Then transfer it into the bowl with the shredded chicken.
Add the BBQ sauce to the bowl and mix until the chicken is evenly coated in sauce.
Slice the rolls in half lengthwise leaving them intact, and place the bottom half in the prepared pan.
Spread the BBQ chicken mixture on the bottom rolls evenly and then cover with the top buns.
In a small bowl, combine the melted butter, light brown sugar, and Italian seasoning. Then brush the buns with the melted butter mixture.
Bake in the oven uncovered for 10-15 minutes or until the tops are golden brown.
As it bakes, prepare the slaw. In a medium bowl, combine the coleslaw mix with chopped cilantro, mayo, lime juice, and salt and pepper to taste.
When the sliders have finished baking, lift the top rolls off and spread the slaw over the chicken then cover with the top rolls. Serve with potato chips or fries on the side.