Preheat oven to 325 F. Wash sweet potatoes; prick several times with a fork. Place on a microwave-safe plate. Microwave on 100 percent power (high) for 4 to 6 minutes or until tender; cool at least 20 minutes. Peel potatoes and cut into 1/2-inch cubes; set aside.
Meanwhile, in a large skillet cook bacon until crisp; drain bacon on paper towels. Reserving drippings in skillet. Crumble bacon; set aside. Measure drippings. If necessary, add butter to drippings to make 3 tablespoons. Cook onion in reserved drippings over medium heat until just tender. Add garlic; cook 30 seconds. Add collard greens or chard and cook 5 minutes more or until tender.
In bowl combine potatoes, bacon, onion mixture, stuffing mix, pecans, parsley, and pepper. Add enough broth to moisten, toss lightly to combine. Transfer to a 2-quart casserole or baking dish; cover. (Or use to stuff an 8- to 10-pound turkey.) Bake casserole about 45 minutes or until heated through (165F). Makes 8 to 10 servings.