1. Place cooked chicken breast on a cutting board and chop into small, even bite-sized pieces. Keeping the pieces uniform helps the dressing coat evenly and improves the overall texture.

2. Finely chop celery and parsley, then mince the garlic into very small pieces. Smaller cuts help distribute flavor throughout the salad without overpowering any bite.

3. In a large mixing bowl, combine Greek yogurt, olive oil, fresh lemon juice, lemon zest, minced garlic, dried oregano, salt, and black pepper. Stir continuously for about 1 to 2 minutes until the mixture becomes smooth, creamy, and fully blended with no lumps.

4. Add the chopped chicken, celery, and parsley into the bowl. Using a spoon or spatula, gently fold everything together for about 1 minute until all ingredients are evenly coated with the dressing. Avoid overmixing to keep the chicken tender.

5. Cover the bowl and refrigerate for 20 to 30 minutes. This resting time allows the lemon and garlic flavors to fully blend into the chicken and slightly thickens the dressing.

6. Before serving, stir lightly to redistribute the dressing. If the salad feels slightly thick, add 1 to 2 teaspoons of olive oil or yogurt and mix gently until the texture becomes creamy again.