In a large skillet, cook bacon over medium heat until crisp. Drain bacon pieces on paper towels, reserving 1 tablespoon drippings in skillet.
Cook onion in reserved hot bacon drippings about 5 minutes or until tender.
In a greased 2-quart casserole, combine pork and beans, bacon and the onion. In a small bowl, combine brown sugar, ketchup, mustard, garlic powder and chili powder. Pour ketchup mixture over bean mixture; stir gently to coat.
Bake, uncovered, in a 350 degree F oven for 50 to 60 minutes or until heated through and desired consistency. Stir gently before serving. Makes 8 servings.