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.
Spoon meat mixture evenly into taco shells; top with lettuce and cheese.
Drain remaining can of tomatoes; spoon evenly over tacos.
COOK'S TIPS: For a milder flavor, use Ro*Tel® Mild Diced Tomatoes & Green Chilies. Draining the liquid off the second can of tomatoes reduces the spiciness of the tomatoes used on top of the tacos.