Preheat the oved to 350F and lightly coat a rimmed baking sheet with cooking spray.
Wash the chicken pieces and pat them dry so that the seasoning can adhere. Put the chicken on the prepared baking sheet. Do not remove the skin or bones from the chicken.
Generously salt and pepper the chicken pieces on both sides. Then, generously sprinkle the Mexican oregano all over the chicken. By generously, I mean that the tops should nearly be covered in it.
Bake the chicken:
Bake for about 45 minutes, until the chicken's internal temperature reaches 165F for breasts and 170F for thighs. Cooking time will vary by the size of the chicken pieces.
Remove the chicken from the oven and allow the chicken to rest for 5 minutes. Remove the skin and bones from the chicken pieces and shred the meat with two forks or by pulling it apart with your hands. I also like to take the chicken juices form the pan and toss it with the shredded chicken before serving for added flavor.
Assemble the tacos:
To assemble the tacos, put some chicken on each tortilla and top with pico de gallo, avocado, and sour cream.