Place the chicken breast in a small pot and cover with water or broth; bring to a gentle simmer and cook for 12-15 minutes until fully cooked through.
Remove the chicken from the liquid and use two forks to shred the meat into thin strands.
While the chicken cooks, thinly slice the Anaheim peppers and red onion.
Heat the avocado oil in a skillet over medium-high heat. Add the peppers and onions, sautéing for 5-7 minutes until they develop a slight char and become tender.
Add the shredded chicken to the skillet along with the sea salt, black pepper, cumin, and chili powder. Toss well to combine and heat through for 2 minutes.
Warm the corn tortillas in a dry pan or over an open flame for 30 seconds per side until pliable.
Divide the chicken and pepper mixture evenly among the three tortillas.
Top each taco with sliced avocado, fresh cilantro, and a squeeze of lime juice before serving.