Preheat oven to 375 degrees.

Scatter onion, garlic and bell pepper in a shallow baking dish or oven safe skillet

Salt and pepper chicken breasts; nestle them in with the garlic, onion and peppers.

In a small mixing cup combine stock, and spices; pour over chicken and vegetables. Cover, and cook until chicken is cooked through, about 45-55 minutes. Remove from oven and let stand to cool slightly.

When the chicken is done, and slightly cooled enough to handle, pull off the bone and shred with two forks. Discard bones and mix with the peppers and onions it cooked in. Cover until ready to use.

While the chicken is cooking heat a heavy, dry skillet to medium high heat. Do not oil. Add onion quarters, whole garlic cloves and whole hot pepper. In the same dry skillet, add ancho chillies and toast until chilies are toasted, around 45 seconds, and black marks appear on vegetables, about 3 minutes.

The chillies will be done in seconds, much quicker than the onion, garlic and pepper; when they are done, place toasted chillies in a bowl and pour hot water over them to submerge and rehydrate. Let them soak for 20 minutes.

When black marks have appeared on the onion quarters, garlic cloves and pepper, remove from pan.

Remove stem and seeds from hot pepper, and add to a bowl, blender or food processor. Add onion quarters and garlic. Drain the liquid from the ancho chillies and remove their stems and seeds; add the the bowl/blender/processor.

Add the crushed pineapple, mango chunks, vinegar, lime, spices, water and salt.

Blend in the bowl with an immersion blender (or blender/food processor) until completely smooth. If it is still too thick, add a tablespoon or two more water.

Warm corn tortillas on a skillet, top with shredded chicken, lots of hot sauce and serve with cilantro, lime and avocado.