In a mixing bowl, combine the diced chicken, 1 ½ tablespoons flour, and 1 tablespoon of sweet paprika, tossing to coat the chicken evenly.
In a large skillet or Dutch oven, melt 2 tablespoons of butter over medium heat. Add the coated chicken and cook until both sides are golden and the chicken is cooked through. Using a slotted spoon, transfer the chicken to a plate.
Add the remaining butter to the skillet and melt over medium heat. Stir in the chopped onions, cooking until they become soft and translucent. Reduce the heat to low, add the minced garlic, and cook for an additional minute, stirring constantly.
Sprinkle the remaining flour and paprika into the skillet, stirring for about 2 minutes to incorporate. Gradually pour in the chicken broth, whisking continuously until combined. Allow the mixture to simmer on low heat until it thickens. Season with kosher salt and freshly ground black pepper to taste.
With the heat as low as possible, gently stir in the sour cream. Return the cooked chicken and any accumulated juices to the skillet, folding it into the sauce. Garnish with chopped parsley.