In a mixing bowl, combine mayonnaise, apple cider vinegar, and sugar, whisking until smooth. Add shredded green cabbage, purple cabbage, and shredded carrots, mixing well. Cover and chill in the refrigerator for at least 30 minutes.

In another bowl, whisk together mayonnaise, sour cream, and milk until smooth. Incorporate minced garlic, seasoning with salt and pepper to taste.

In a saucepan over medium heat, combine honey, chopped chipotle peppers, and ketchup. Stir frequently for about 5-7 minutes until thickened and glossy.

Preheat grill to medium-high heat. Pound chicken thighs to 1 inch thick, season with salt and pepper, then grill for 5-7 minutes per side until golden brown and cooked through.

While chicken is warm, place in a bowl and pour honey chipotle sauce over. Toss until evenly coated.

Melt unsalted butter in a skillet. Brush onto cut sides of brioche buns. Toast cut-side down for about 2 minutes until golden brown.

Assemble sliders by placing glazed chicken on the bottom half of each bun, topping with coleslaw and creamy garlic sauce, then adding the top bun.