Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the shredded turkey, cooked pasta, frozen mixed vegetables, cream of mushroom soup, and milk. Stir well until all ingredients are evenly mixed.
Add the garlic powder, onion powder, black pepper, and salt to the mixture. Stir to incorporate the seasonings.
Transfer the turkey mixture to a greased 9x13 inch baking dish, spreading it evenly.
Sprinkle the shredded cheddar cheese over the top of the casserole.
If using breadcrumbs, mix them with olive oil in a small bowl until they're coated. Sprinkle the breadcrumb mixture evenly over the cheese layer for added crunch.
Cover the baking dish with aluminum foil (optional) and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and bake for an additional 15 minutes or until the casserole is bubbly and the cheese is golden brown.
Remove from the oven and let it cool for a few minutes before serving.