In a small skillet over medium heat, melt butter until frothy. Add celery,green onion and garlic to the butter and cook until the celery is softened and garlic is golden, about 2 minutes. Remove from heat and set aside.
In a large bowl, combine using a fork, the beef, sausage, bread crumbs, milk, salt, pepper, celery mixture and 3/4 cup of chili sauce.
Transfer mixture to a 9 x 12 baking dish. Form meat mixture into a loaf. Top with the remaining chili sauce, spreading evenly to cover. Place potatoes around the loaf, cut sides down.
Bake for 60 - 70 minutes, or until meat thermometer inserted in center reaches 160°F.
If making potatoes, baste potatoes with drippings halfway thru cooking time.