Cook pasta according to package directions, making sure to salt the water after it comes to a boil and before adding the pasta. When the pasta is done cooking, drain well then place in a large bowl.

While the pasta cooks, make the dressing. In a large bowl combine mayo, buttermilk, sugar, dried parsley, garlic powder, dried dill, dried chives, and black pepper. Stir to combine.

Toss the cooked, warm pasta with 1/2 of the chopped green onions and 1.5 tablespoons apple cider vinegar. Place in the refrigerator to cool for 20 minutes.

After 20 minutes, remove the pasta from the refrigerator. Stir in dressing, shredded cheddar cheese, remaining green onions, tomatoes, bacon, and toss in diced chicken. Stir until well combined.

Refrigerate for at least 1 hour, but ideally 4 hours before serving.