Preheat oven to 350°F.

Boil chicken breasts in a large pot until fully cooked.

Shred the cooked chicken with a fork.

In a large skillet, combine the shredded chicken, diced tomatoes with green chilies, and diced onion.

Cook over medium heat until onions are translucent.

Add tomato sauce, taco seasoning, diced black olives, and taco sauce to the skillet.

Reduce heat to low and simmer for 10 minutes.

Slice bell peppers in half lengthwise and remove seeds.

Place bell pepper halves on a cookie sheet, cut side down, and bake in the preheated oven for 10-12 minutes.

Remove from oven and drain any juice from the peppers.

Fill each bell pepper half with the chicken mixture.

Top the filled peppers with shredded Mexican cheese.

Bake in the 350°F oven for approximately 40-45 minutes, or until cheese is melted and bubbly.