In a large pot combine onion, garlic, sweet potato, and turkey stock. Bring to a boil and reduce. Cook until sweet potato is completely soft. Remove from heat and puree. Set aside and let cool down.
In a large bowl combine ground turkey and beef along with eggs, breadcrumbs, salt, pepper, chili and 2 tbsp. barbecue sauce. Fold in cooled down sweet potato puree.
Pour meatloaf into two bread baking pans or into one larger casserole dish. Spread ¼ cup of barbecue sauce on top of meatloaf.
Bake at 375 °F for about 60 minutes or until meat is cooked through and reaches 160 °F internal temperature. Pour the remaining barbecue sauce over the top and bake for another 15 minutes.
Remove from oven and let meatloaf set for about 10 minutes. Serve and enjoy.