Heat a 12" sauté or frying pan over high heat. Add the oil, once it is heated add the chopped onion and paprika and sauté until the onion softens and is almost transparent.
Move the onion off to the side of the pan and add the chicken breasts. Brown the breasts on both sides about 3-4 minutes per side.
Add the chicken broth and simmer, covered for about 15 minutes. Remove the pan from the heat. Stir the flour into the sour cream until it is well incorporated. Then add the sour cream to the pan and stir until the sauce is smooth. You can put the pan back on low to keep the chicken warm if necessary but don't allow it to boil or the sour cream will separate.