Preheat oven to 400 degrees Fahrenheit.

Finely dice the sweet onion.

Sauté the diced onion in salted butter and extra virgin olive oil over medium heat for 5 minutes.

Thinly slice the 2 large sweet potatoes.

Rinse and drain the can of black beans.

In a large bowl, combine the sautéed onion, sweet potatoes, black beans, and 2 teaspoons of taco seasoning.

Mix well to ensure even distribution of seasoning.

Dump the mixture into a large glass baking dish.

Cover the baking dish tightly with foil.

Bake in the preheated oven for 50 minutes.

Cut the boneless skinless chicken breasts into small pieces.

Combine the remaining 1 teaspoon of taco seasoning with the chicken pieces.

Evenly distribute the seasoned chicken over the potato and bean mixture in the baking dish.

Recover the baking dish with foil.

Bake for an additional 20 minutes, or until the chicken is cooked through.

Remove the baking dish from the oven.

Finely chop the fresh parsley.

Top the dish with the chopped fresh parsley and freshly shredded white cheddar cheese.

Recover the baking dish (no oven required) for 5 to 10 minutes, or until the cheese has melted from the steam and heat.

Serve hot with sour cream, avocado, and olives if desired.