1. Cook beef in large skillet over medium-high heat about 7 minutes or until crumbled and no longer pink, stirring occasionally; drain. Add 1 can undrained tomatoes and seasoning mix; mix well. Gradually add water, stirring until well blended. Bring to a boil. Reduce heat to low; simmer 10 minutes, stirring occasionally.
2. Spoon meat mixture evenly into taco shells; top with lettuce and cheese.
3. Drain remaining can of tomatoes; spoon evenly over tacos.