Heat olive oil in an oven-safe skillet over medium-high heat. Sear chicken for 2-3 minutes per side until browned.
Add chopped onion and minced garlic to the skillet. Cook until softened, about 5 minutes.
Stir in taco seasoning and water. Bring to a simmer.
Cover the skillet and transfer to the preheated oven. Bake for 20-25 minutes, or until chicken is cooked through and reaches an internal temperature of 165°F (74°C).
Remove chicken from the skillet and shred it using two forks. Return shredded chicken to the skillet and toss with the sauce.
Warm taco shells according to package directions.
Fill warm taco shells with the chicken mixture and your favorite toppings.
Notes
For extra flavor, you can add a pinch of cumin and chili powder to the taco seasoning.
If you don’t have an oven-safe skillet, you can transfer the mixture to a baking dish before putting it in the oven.
Serve with a side of rice and beans for a complete meal.