Prepare the Sauce: In a food processor or blender, combine the mayonnaise, plain Greek yogurt, fresh basil leaves, minced garlic, olive oil, lemon juice, lemon zest, cumin, sea salt, and black pepper. Blend until smooth and creamy, about 1-2 minutes.

Shred the Chicken: Remove the rotisserie chicken from its packaging and let it cool slightly. Shred the chicken into bite-sized pieces.

Chop the Vegetables: Wash and chop the celery and red onion into small, uniform pieces.

Combine Ingredients: In a large mixing bowl, combine the shredded chicken, chopped celery, and red onion. Pour the creamy sauce over the mixture and fold everything together until well combined.

Chill and Serve: Cover and refrigerate the salad for at least 30 minutes. Stir gently before serving.