Prepare the Chicken: Trim any excess fat from the chicken breasts or thighs. If the chicken breasts or thighs are too thick, you can butterfly them to ensure even cooking. Pat the chicken dry with paper towels and season both sides with salt and pepper.
Sauté the Onion and Garlic: Heat the oil over medium-high heat in a large skillet or pot. Add the finely chopped onion and sauté for about 2-3 minutes until it becomes translucent. Add the minced garlic and cook for an additional minute, being careful not to burn it.
Add the Spices: Lower the heat to medium. Add the chili powder, garlic powder, onion powder, paprika, ground cumin, and oregano to the skillet. Stir the spices with the onions and garlic until fragrant, about 1 minute. Add tomato paste; stir and cook for one more minute.
Brown the Chicken: Push the onion and spice mixture to the sides of the skillet, making space in the center. Place the seasoned chicken breasts or thighs in the center of the skillet. Cook each side for about 2-3 minutes until lightly browned.
Add Liquid and Simmer: Pour the diced tomatoes and chicken broth into the skillet. Bring it to a simmer. Reduce heat to medium-low, cover the skillet with a lid, and let the chicken cook for about 15-20 minutes until it reaches an internal temperature of 165°F (74°C) and is fully cooked. The cooking time may vary depending on the thickness of the chicken.
Shred the Chicken: Once the chicken is cooked, remove it from the skillet and place it on a cutting board. Use two forks to shred the chicken. Return the shredded chicken to the skillet and toss it with the sauce, coating the chicken evenly. Let it simmer for 5-10 minutes, or the sauce reduces and thickens slightly.
Serve: Garnish with chopped cilantro, if desired. Use it to make tacos, quesadillas, empanadas, sandwiches, or arepas. Add it to a baked potato with some sharp cheddar cheese or a salad (cold). It's incredibly versatile and can be stored in the refrigerator for a few days or frozen for future use.