In a large bowl, whisk together mayonnaise, apple cider vinegar, and sugar until smooth. Add the shredded green and purple cabbage along with the shredded carrots, tossing well to ensure everything is coated in the dressing. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes.

In a separate bowl, combine mayonnaise, sour cream, milk, and minced garlic. Stir the mixture until creamy and well blended. Set aside for the flavors to develop while you prepare the chicken and sauce.

In a small saucepan over medium heat, combine honey, chipotle peppers in adobo, and ketchup. Stir gently and bring to a simmer, allowing it to bubble for 3-5 minutes until it thickens slightly and becomes glossy. Remove from heat and set aside to cool.

Preheat your grill to medium-high and lightly oil the grates. Pound the boneless skinless chicken thighs to ensure even thickness. Season the chicken with olive oil, kosher salt, and black pepper. Grill for 5-7 minutes on each side until fully cooked.

Transfer the grilled chicken thighs to a mixing bowl and pour the prepared honey chipotle sauce over the chicken, tossing gently until each piece is evenly coated.

In a skillet over medium heat, melt some unsalted butter. Place the cut sides of the brioche slider buns in the skillet, toasting until golden brown and slightly crispy, about 2-3 minutes.

To assemble your sliders, start with a toasted brioche bun base. Layer on a piece of honey chipotle chicken, top with coleslaw, drizzle the creamy garlic sauce over the slaw, and finish with the top half of the bun.