Prep the chicken: Trim excess fat.
Pat dry. Season lightly with salt and pepper on both sides.
Make the sauce base: In a bowl, stir together BBQ sauce, onion, garlic, apple cider vinegar, brown sugar, smoked paprika, chili powder, black pepper, and any cayenne or hot sauce.
Load the slow cooker: Place the chicken in the slow cooker. Pour the sauce over the top, turning pieces so they’re coated.
Set and cook: Cook on Low for 4–6 hours or High for 2.5–3.5 hours.
Thighs usually take the longer end; breasts cook a bit faster. The chicken is done when it shreds easily and hits 165°F internally.
Shred the chicken: Transfer cooked chicken to a cutting board and shred with two forks. Skim any excess fat from the sauce if needed.
Reduce or thicken (optional): If the sauce is thin, you have options: Return shredded chicken to the slow cooker and let it sit on Warm for 10–15 minutes to absorb.
Or simmer some sauce in a small saucepan for 5–10 minutes to thicken before mixing back in.
For extra gloss, stir in 1 tablespoon butter at the end.
Adjust to taste: Add a splash of vinegar or lemon for brightness, more brown sugar for sweetness, or a dash of hot sauce for heat.
Serve: Spoon onto toasted buns with coleslaw and pickles, over rice or mashed potatoes, or wrap in tortillas with crunchy cabbage and a squeeze of lime.