Preheat oven to 200°F. Warm taco shells on a baking sheet for about 10 minutes in oven while preparing turkey.
Heat oil in a large skillet over medium heat. Add turkey and brown, stirring occasionally. Stir in seasoning mix and 1/4 cup water. Continue cooking until liquid has evaporated and turkey is cooked through.
Stuff taco shells with turkey meat, then fill with tomatoes, onions, pico de gallo, avocados or guacamole, cheese or cilantro, if desired.
