Cook the pasta in boiling salted water to al dente according to the package directions. Drain, rinse, and let cool completely.
Season the chicken with the paprika, garlic powder, ½ teaspoon of salt, and ¼ teaspoon pepper.
Heat the oil in a large skillet over medium heat until hot. Add the chicken and cook 5 to 6 minutes on each side or until cooked through. Remove the chicken from the skillet and let cool before coarsely chopping.
Make the dressing: Whisk together the mayonnaise, sour cream, onion, sugar, vinegar, and remaining salt and pepper in a medium bowl.
Combine the pasta, chicken, celery, carrot, dill, and parsley in a large bowl. Pour the dressing over the top and toss to coat. Cover and refrigerate until ready to serve. Garnish with more parsley and dill before serving.