Bring a large pot of salted water to a rolling boil. Add the rotini pasta and cook according to package directions until al dente, about 8-10 minutes. Drain and rinse under cold water to stop cooking. Set aside to cool.

In a medium mixing bowl, whisk together mayonnaise, Greek yogurt, Parmesan cheese, lemon juice, Dijon mustard, and minced garlic until smooth and creamy. Season with salt and pepper to taste.

In a large mixing bowl, combine the cooled pasta, shredded chicken, and chopped romaine lettuce. Gently toss to mix evenly.

Pour the dressing over the pasta mixture and gently fold until everything is coated evenly.

Sprinkle croutons on top and gently toss again before serving.