Sprinkle the chicken with the paprika, salt and half the pepper. Spray a large nonstick skillet with oil spray and set over med-hi heat. Add the chicken and cook until browned on all sides, 8 to 10 minutes. Transfer to crockpot.
Add the leeks, mushrooms and carrots to the skillet; cook, stirring occasionally, until the vegetables begin to soften. Add the broth and cook about 2 minutes longer. Pour vegetable mixture over the chicken. Add the tapioca, poultry seasoning and the remaining salt and pepper to crockpot and mix well. Cover and cook on LOW for 5 to 6 hours. Serve sprinkled with dill.