In a large mixing bowl, combine 2 cups of shredded cooked chicken with 1 tablespoon of olive oil, 1 teaspoon of garlic powder, 1 teaspoon of cumin, 1/2 teaspoon of salt, and 1/4 teaspoon of black pepper. Stir well until the chicken is evenly coated with the spices, and mix in 1/4 cup of shredded cheese.

In a medium bowl, whisk together 1 cup of Greek yogurt and 1/4 cup of milk until smooth and creamy. Season with 1 teaspoon of garlic powder, 1/2 teaspoon of salt, and a pinch of black pepper.

Preheat your oven to 375°F (190°C) while lightly greasing a baking dish. Spread a layer of the creamy white sauce evenly at the bottom of the dish.

Warm the whole wheat tortillas briefly in a dry skillet or microwave to make them pliable. Spoon a generous amount of the chicken filling onto each tortilla, then roll tightly and place seam-side down in the prepared baking dish.

Once all the enchiladas are in the baking dish, pour the remaining white sauce evenly over the top and sprinkle with additional shredded cheese.

Transfer the dish to the preheated oven and bake for 25-30 minutes, or until the cheese is melted and golden brown.

Once baked, remove the enchiladas from the oven and let them rest for 5-10 minutes before serving.