Begin by preheating your oven to 375°F (190°C) to ensure it is hot and ready for baking.
In a large mixing bowl, combine the shredded chicken, frozen mixed vegetables, cream of chicken soup, milk, garlic powder, onion powder, thyme, salt, and pepper. Mix thoroughly until all ingredients are well blended and coated in the creamy mixture.
Take a greased 9x13 inch casserole dish and carefully pour the chicken and vegetable mixture into it, spreading it evenly across the bottom.
Next, sprinkle the shredded cheddar cheese evenly over the chicken mixture.
Unroll the crescent roll dough and gently lay it over the cheese layer, pressing the seams together firmly.
Drizzle olive oil over the crescent dough, and sprinkle a touch more salt and black pepper on top.
Place the casserole in the preheated oven and bake for 25-30 minutes, or until the crescent dough is golden brown and fully cooked.
Once baking is complete, allow the casserole to cool for about 5 minutes before slicing and serving.
Notes
For an appealing dish, cut the casserole into squares and garnish with a sprinkle of chopped fresh parsley.