Cook the pasta: Bring a large pot of salted water to a boil.
Cook pasta until just al dente, following package times. Drain and rinse under cold water to stop the cooking. Toss with a drizzle of olive oil to prevent sticking.
Mix the dressing: In a bowl or jar, whisk together mayonnaise, Greek yogurt, Dijon, red wine vinegar, olive oil, honey, garlic, oregano, salt, and pepper.
Taste and adjust acidity or salt as needed.
Prep the mix-ins: While the pasta cools, chop the chicken, tomatoes, cucumber, red onion, bell pepper, celery, and olives. Crumble or shred the cheese. Chop the parsley.
Combine the salad: In a large bowl, add the cooled pasta, chicken, veggies, olives, cheese, and parsley.
Pour over about two-thirds of the dressing.
Toss gently: Use two large spoons to combine until everything is evenly coated. Add more dressing as needed to reach your preferred creaminess.
Chill for flavor: Cover and refrigerate for at least 30 minutes, ideally 1–2 hours. The pasta will absorb some dressing as it rests.
Final seasoning: Before serving, taste and add a pinch of salt, a squeeze of lemon, or extra dressing if the salad seems dry.