Season the chicken strips with salt, pepper, and paprika.
In a large skillet, heat 2 tablespoons olive oil and add the chicken pieces. Cook, stirring, until cooked through. For the breast it's 3-5 minutes, for thighs 8-10 minutes. When done, transfer the chicken to a bowl and set aside.
In the same skillet, heat the remaining tablespoon olive oil and cook the onion, stirring, until it starts to soften, for about 6-8 minutes. Add the bell pepper, garlic, tomato paste, and cook for a minute more.
Add the chicken stock and bring to a boil. Add the chicken pieces, reduce the heat, cover the skillet, and cook for about 5 minutes, until the chicken is warmed through.
Meanwhile, in a small bowl, combine the sour cream and flour. Add this mixture to a chicken and stir well. Cook for 4-5 minutes more, until the sauce thickens a little bit. But don't let the sauce boil.
Taste and season more with salt and pepper, if needed. Garnish with some chopped parsley and serve. Enjoy!