In 10-inch nonstick skillet, cook beef and onion over medium-high heat 5 to 7 minutes, stirring frequently, until thoroughly cooked; drain. Stir in taco seasoning mix and water. Reduce heat to medium; cook 3 to 4 minutes, stirring frequently, until thickened. Stir in dip until well mixed.
Heat taco shells and tortillas as directed on box.
Fill heated taco shells and tortillas with warm beef mixture, lettuce, tomato and bacon.