Bring a large pot of salted water to a boil. Add pasta and cook according to package directions until tender. Drain pasta in a colander. Rinse pasta under cold water until cooled. Drain well.
Add cooled pasta to a large mixing bowl. Add chicken, cherry tomatoes, mozzarella pearls, Parmesan cheese, and basil.
In a small mixing bowl, whisk marinara sauce, olive oil, red wine vinegar, Dijon mustard, Italian seasoning, garlic powder, salt, black pepper, and crushed red pepper flakes.
Pour dressing over pasta mixture. Toss until evenly coated. Cover and refrigerate for at least 30 minutes
Stir before serving Sprinkle with seasoned breadcrumbs right before serving, if using.
Notes
Storing
Store in Refrigerator - Place leftovers in an airtight container and refrigerate for up to 3 days.Store Breadcrumbs Separately - Keep the breadcrumbs in a separate container and add them right before serving.Do Not Freeze - This pasta salad does not freeze well because the pasta, tomatoes, and mozzarella can change texture.