In 12-inch nonstick skillet or Dutch oven, brown ground beef over medium heat 8 to 10 minutes or until thoroughly cooked, stirring frequently. Drain well.
In 3 1/2- to 4-quart slow cooker, mix cooked ground beef and remaining ingredients except buns.
Cover; cook on Low heat setting 4 to 6 hours.
To serve, stir beef mixture. Spoon 1/2 cup beef mixture into each bun.