Preheat oven to 300°F
Line a baking dish with parchment paper.
Mix all spices together.
Place chicken in a bowl and coat with the spice mix.
Add coated chicken breasts to prepared baking dish
Pour chicken stock over chicken breasts
Cover dish tightly with foil
Cook in preheated oven for 30-40 minutes or until chicken is cooked through and internal temperature is 165°F
Remove from oven and let rest covered for 10 minutes
Remove chicken to a cutting board and reserve liquid
Shred chicken or chop into small pieces
Toss shredded chicken with reserved liquid, adding liquid a tablespoon at a time to keep chicken moist
Serve on tortillas with taco sauce, lettuce, tomato and cheese