Preheat oven to 375 degrees Fahrenheit.

Make your chicken. Heat up a large enameled cast-iron skillet or oven-safe pan (I used 12 inches - it needs to be large) over medium heat. Add oil and let it get hot. Add chicken, 1 tablespoon taco seasoning, salt, and pepper, and saute for 2-3 minutes until browned on the outside (chicken does not have to be cooked all the way through). Remove from pan and set aside.

Make your vegetables. To the same pan, add onions, a little salt and pepper, and saute for 2-3 minutes until slightly softened. If needed, add a splash of broth (you can use some from the amount you measured out) if you need to deglaze the pan. Add peppers and remaining taco seasoning and saute for another 2-3 minutes.

Mix your casserole. Add rice and mix well to combine and let toast for 1-2 minutes. Add in the cooked chicken, fire-roasted tomatoes, green chiles, and mushrooms, and mix well to combine. Add broth and carefully stir to make sure it is well incorporated. You want to make sure you have enough liquid so you can see a little on the top, but not submerge everything. Not enough liquid and you will be left with uncooked rice. Too much and it will be too soggy and won't absorb. See the pictures for reference.

Bake. Cover with tin foil and bake for 45 minutes. Remove the foil and bake for another 10-15 minutes until the liquid is absorbed. The rice should be cooked through and fluffy. Remove from oven, sprinkle with shredded cheese, and bake for another 1-2 minutes until cheese is melted.

Enjoy! Top with optional toppings or topping of choice and enjoy!