In slow cooker, combine chicken, garlic, salsa, chilies, chili powder, 1 teaspoon salt and 1/4 teaspoon pepper. Cover; cook on high for 4 hours (or on low for 8 hours).
Transfer chicken to a serving bowl and shred, using two forks; moisten with cooking juices. Serve in taco shells, with toppings if desired.
Oven method: Preheat oven to 350 degrees. Use a 5-quart Dutch oven with a tight-fitting lid instead of the slow cooker; add 2 cups water. Cover; bake until chicken is fork-tender, about 2 hours. Finish as indicated above.
Nutrition information per serving:
Calories416Fat15 gCarbohydrates21 gSaturated fat3Protein47 gDietary fiber2 g