In a large mixing bowl, combine shredded cooked chicken with olive oil, garlic powder, cumin, salt, and black pepper. Mix thoroughly until the spices evenly coat the chicken. Fold in shredded cheese and set aside.

In a medium bowl, whisk together Greek yogurt and milk until smooth and creamy. Season this mixture with garlic powder, salt, and a pinch of black pepper.

Preheat your oven to 375°F (190°C) and grease a baking dish with non-stick spray or olive oil. Spread white sauce across the bottom of the dish.

Warm whole wheat tortillas in a skillet or microwave for about 30 seconds. Spoon chicken filling onto each tortilla, roll tightly, and place seam-side down in the baking dish.

Pour remaining white sauce over the top of the enchiladas and sprinkle shredded cheese on top.

Bake for 25-30 minutes until bubbly and cheese is golden brown.

Let the dish rest for 5-10 minutes before serving. Garnish with chopped cilantro if desired.