Cook pasta in salted boiling water until al dente, about 8-9 minutes. Drain, rinse with cold water, drizzle with olive oil, and cool completely.
If cooking from scratch, season chicken breasts and cook in a skillet over medium-high heat for 6-7 minutes per side until internal temperature reaches 165°F (74°C). Let rest, then dice or shred into bite-sized pieces.
Slice cherry tomatoes in half, dice cucumber, thinly slice celery, finely dice red onion, drain black olives, and roughly chop fresh parsley.
In a small bowl, whisk together mayonnaise, red wine vinegar, Dijon mustard, garlic powder, onion powder, Italian seasoning, salt, and pepper until smooth and combined.
In a large mixing bowl, combine cooled pasta, diced chicken, cherry tomatoes, cucumber, celery, red onion, black olives, and fresh parsley.
Pour dressing over the salad and toss gently but thoroughly until every ingredient is evenly coated. Taste and adjust seasoning as needed.
Cover and refrigerate for at least 30 minutes to allow flavors to meld. Stir again before serving, adding extra dressing if needed.