Poach the chicken: Place the chicken breasts in a saucepan and cover them with water. Bring the water to a boil, then reduce the heat and let it simmer for 10-12 minutes, or until the internal temperature of the chicken reaches 165°F/74°C. Use a kitchen thermometer to check for doneness.
Shred the chicken: Once cooked, transfer the chicken to a cutting board or bowl, and use two forks to shred it into bite-sized pieces.
Sauté the aromatics: In a skillet, heat the vegetable oil over medium heat. Add the minced onion and sauté until it's soft and translucent, about 3 minutes. Then, add the minced garlic and sauté for another 30 seconds.
Season the chicken: To the skillet, add the ground cumin, dried oregano, chili powder, and salt. Stir to combine and let the spices cook for about a minute to release their flavors.
Add salsa: Pour in the salsa and give everything a good mix. If the mixture seems too thick, you can add a splash of water to loosen it up.
Combine everything: Add the shredded chicken to the skillet and stir it into the sauce. Let it simmer for 2-3 minutes to allow the flavors to meld together.
Serve: Warm up your tortillas or taco shells, then spoon the delicious shredded chicken mixture onto them. Top with your favorite taco toppings and enjoy!