In a medium bowl, toss the chicken with salt, pepper, garlic powder, and paprika. Set aside.
In a large nonstick cast iron or skillet, heat oil over medium-high heat.
Once oil or butter is heated, place thighs skin side down and sear for about 3 minutes or until brown. Flip chicken over on the other side and brown for another 3 minutes. Remove and set aside.
Add the onions, garlic, and bay leaf ; cook, stirring often, 3 to 4 minutes.
Stir in bell pepper, paprika and continue cooking , stirring until soft, about 2-3 minutes.
Pour in the broth, salt and return the chicken back to the pot, together with all its juice.
Cover and cook for about 35 minutes or until chicken is fully cooked through and has reached desired tenderness.
In a small bowl, stir the flour into the sour cream and milk mixture to form a smooth paste.
Push chicken thigh aside and add the sour cream mixture into the sauce, stirring until mixture is fully combine with the sauce.
Let it cook on very low heat until the sauce thickens about 3-5 minutes. Adjust seasonings with salt, stock and pepper to taste.
Serve with pasta or rice.