Start by whisking together Greek yogurt or sour cream, mayo, dried parsley, dried chives, dried dill, garlic powder, onion powder, Worcestershire sauce, salt, and pepper in a jar until smooth; add buttermilk gradually to reach your desired consistency.
Bring a large pot of salted water to a rolling boil and cook the short cut pasta until it is al dente, then drain well.
Place the warm pasta in a big bowl and mix in the salsa verde and shredded chicken, then drizzle the dressing over and stir thoroughly to coat everything evenly.
Add the cubed cheddar cheeses, shredded romaine, halved cherry tomatoes, chopped cilantro, and crumbled bacon to the bowl, tossing gently to combine all ingredients.
Finish by sprinkling the diced avocado on top right before serving.
Enjoy this pasta salad either warm or chilled for a fresh and creamy meal!