If using chicken in this pasta salad, cut it up and add it to a bowl with Tony's Creole Style Chicken Marinade. Give it a good stir, then cover the bowl and refrigerate it for 30 minutes.
Cook your pasta. Once it's done, rinse it with cool water and drain it thoroughly before adding it to a large bowl.
Meanwhile, prep your other ingredients and make the dressing. Combine the dressing ingredients in a medium bowl until smooth (mayo, sour cream, horseradish, lemon juice, Worcestershire sauce, garlic, and Tony's Creole Seasoning).
Once the chicken is done marinating, add it to a skillet over medium-high heat. Cook until the chicken is done (about 5-6 minutes), stirring fairly often. Take it off the heat and let it cool a bit.
It's time to assemble your pasta salad! Add the remaining salad ingredients (onion, tomatoes, peppers, parsley), along with the chicken (spoon it out of the pan leaving any extra marinade behind) and dressing to the macaroni. Give it a good stir. You can eat it immediately or chill (make sure it's covered) for an hour first.