Spray large slow cooker with cooking spray.
Season chicken with ½ teaspoon salt and ¼ teaspoon of pepper. In 12-inch skillet, heat oil over medium-high heat. Place chicken skin-side down in skillet. Cook 8 to 10 minutes, turning once, until brown on both sides. Transfer chicken to slow cooker.
In the skillet on medium heat, add onions and cook about 4 minutes, stirring frequently. Add garlic, paprika, red pepper and rest of the salt and pepper; continue to cook and stir for about 1 minute. Transfer to slow cooker. Add chicken broth to skillet, scraping any brown bits on bottom of skillet. Transfer to slow cooker.