Chop the onion. You can use ½ cup frozen chopped onions or 1 ½ teaspoons onion powder.
Cook:
Heat a large skillet over medium-high heat. Once hot, add the oil and the chopped onion. Cook it while stirring for about 2 minutes. Then, add the ground chicken and the taco seasoning to the skillet.
Cook the ground chicken for about 7 minutes, while breaking up the chunks with a wooden spoon into small pieces as it cooks. Once cooked, drain off any excess fat.
While the chicken is cooking, heat your crunchy taco shells according to the package directions or in the oven preheated to 325F for approx. 6 minutes or lay your tortillas flat on a baking sheet and warm them up for about the same time and temp. Prepare your toppings.
Serve:
Assemble the tacos by filling each taco shell with the cooked ground chicken and your favorite taco toppings.