In a large mixing bowl, whisk together the mayonnaise, greek yogurt, dijon mustard, fresh lemon juice, and poppy seeds until the dressing is smooth and the poppy seeds are evenly distributed.
Stir in the onion powder, salt, and black pepper. Taste the dressing and adjust the seasoning to your liking.
Add the diced cooked chicken breast and toss until every piece is fully coated in the creamy dressing.
Fold in the dried cranberries and diced celery. Mix gently until they are scattered evenly throughout the salad.
Add the toasted sliced almonds and chopped fresh parsley. Fold them through the salad just until combined so the almonds keep their crunch.
Cover the bowl and refrigerate for at least 30 minutes before serving. Serve on a buttery croissant, on whole grain bread, or scooped onto crispy crackers for a lighter bite.