Bring a large pot of salted water to a boil. Cook pasta according to package directions until al dente. Drain and rinse under cold water to stop cooking. Set aside.
In a skillet over medium heat, cook bacon until crispy. Transfer to a paper towel-lined plate to drain. Once cool, crumble into bits.
In a large bowl, whisk together mayonnaise, sour cream, buttermilk, vinegar, garlic powder, onion powder, dill, chives, salt, and pepper until smooth and creamy.
Add the cooked pasta, chicken, crumbled bacon, cherry tomatoes, cucumber, red bell pepper, red onion, peas, and parsley to the bowl with the dressing. Toss gently until everything is evenly coated.
Cover the bowl and refrigerate for at least 30 minutes to allow flavors to meld. Before serving, taste and adjust seasoning with additional salt and pepper if needed. Serve cold or at room temperature.