Heat 2 tablespoons of the oil in a big skillet over medium-high heat. Add the turkey and garlic and cook until hot and fragrant, stirring frequently. Stir in the bean sprouts, water chestnuts, and 2 cups of the cabbage. Cook for 4 to 5 minutes.
In a small bowl, whisk together the hoisin sauce, soy sauce, brown sugar, cornstarch, and the remaining 2 tablespoons of oil; pour into the skillet and bring to a boil. Cook for 1 minute or until thickened.
Spoon some turkey mixture onto each warmed tortilla and divide the remaining ½ cup of cabbage over the top. Sprinkle with tomato and chow mein noodles. Roll up and enjoy.