Preheat oven to 350°F. Brown ground beef and onion in large skillet on medium-high heat. Drain fat. Stir in broth, vinegar, Worcestershire sauce and Recipe Mix. Bring to boil. Reduce heat and simmer 10 minutes, stirring occasionally or until broth is absorbed. Remove from heat. Stir in cream cheese and 1 cup shredded cheese.
Pour into 2-quart casserole dish. Sprinkle with remaining 1 cup shredded cheese. Bake 10 to 15 minutes or until cheese is melted. Garnish with pickle slices and chopped onions, if desired. Serve with wavy potato chips.