In a saucepan, combine bay leaf, oregano, cilantro, cumin, chili powder, cayenne pepper, salt, pepper, quartered half of onion, chicken breasts, and chicken stock.
Bring to a boil. Reduce heat to a simmer and poach chicken for about 10 – 15 minutes, or until done. Remove chicken breasts to a bowl and shred when cooled.
Add the black beans, tomato sauce, vinegar, garlic powder, chili powder, oregano, cumin, and taco seasoning. Stir to combine.
Fold in the shredded chicken. Reduce heat to medium-low. Cover and let simmer for about 10 to 15 minutes.
Stir in cilantro and remove from heat.
Spray the bottom and sides of a 5×8 baking dish with non-stick spray. Place corn tortillas on the bottom of the baking dish, and half way up the sides, slightly overlapping to coven the entire bottom.
Spoon half the chicken mixture over the tortillas. Sprinkle half the cheese over the mixture. Repeat for a second layer.
Bake at 350 for 35 – 45 minutes until cheese on top is melted. Let stand 5 minutes before cutting. Serve with sliced avocado.
