Preheat the oven to 375°F and coat a 9×13-inch pan with nonstick cooking spray.
In a large mixing bowl, combine ground turkey, chopped onion, minced garlic, bread crumbs, Worcestershire sauce, egg, cottage cheese, and BBQ sauce until well mixed.
Press the turkey mixture evenly into the prepared pan, then bake for 30 minutes.
While the turkey meatloaf is baking, place the potatoes in a pot, cover with water, and cook over medium heat until tender.
Drain the water from the potatoes, then add butter and beat with a hand mixer until smooth.
Stir in sour cream, warm milk, salt, and pepper, mixing until well combined and creamy.
Remove the turkey meatloaf from the oven and drain any excess grease.
Spread the mashed potatoes evenly over the meatloaf, then sprinkle with shredded cheddar cheese and bacon bits.
Return the pan to the oven and bake for another 15 minutes, until the cheese is melted and bubbly.
Serve warm with your favorite sides.