Place the chicken thighs in the slow cooker. Add the sliced onion, minced garlic, smoked paprika, salt, and black pepper.
Pour the barbecue sauce over the top and stir to coat the chicken evenly.
Cover and cook on low for 6 hours until the chicken is very tender.
Shred the chicken directly in the slow cooker using two forks, then stir it into the sauce.
While the chicken finishes cooking, preheat the oven to 425 degrees. Toss the corn pieces with the melted butter, garlic powder, chili powder, salt, and black pepper.
Spread the corn on a baking sheet and roast for 20 minutes, turning once, until the edges turn golden.
Spoon the pulled chicken into bowls or plates and serve the corn ribs alongside. Sprinkle chopped parsley over the corn before eating.