PREHEAT oven to 300°F. Crumble meat with wooden spoon in large frying pan. Brown meat; drain. Stir in seasoning mix and water. Bring to boil; reduce heat to medium. Simmer 10 min., stirring occasionally. Spoon into serving bowl; cover and keep warm.
MEANWHILE, tear lettuce into small bite-sized pieces; place in serving bowl. Spoon cheese, salsa and sour cream each into separate serving bowls.
PLACE taco shells on baking sheet. Bake 3 to 5 min. or until crisp.
SERVE with bowls of seasoned meat, lettuce, cheese, salsa and sour cream. Let everyone build their own tacos.
serving size = 2 tacos + 3 Tbsp. meat