To a 9x13 baking dish add the cubed chicken, oil, and taco seasoning. Stir the ingredients to combine. Over the top of everything add in the black beans and Rotel. Bake for 25 minutes or until the chicken is cooked.
Place taco shells into a 9x13 baking dish. With a slotted spoon removing any liquid so the tacos don't become soggy scoop the chicken mixture into the taco shells. Sprinkle with cheese. Bake for an additional 15 minutes.