1Marinate the chicken breast with garlic powder, sweet paprika, ground cumin, ground cinnamon, salt, dried oregano, vinegar, extra virgin olive oil, and tomato sauce in a container. Let it marinate in the refrigerator for at least 30 minutes, but preferably a few hours.
2In a frying pan, sear the chicken breast on high heat for 2 minutes on each side.
3Add water to the pan and simmer covered over low heat for 8 minutes.
4Remove the pan from the heat and let it rest covered for 5 minutes.
5Remove the chicken, shred it using two forks, and return it to the pan. Cook for 5 minutes until the juices have reduced slightly.
6Assemble the tacos: spread guacamole on the tortillas, add the shredded chicken, pickled onions, and feta cheese (optional).