Preheat oven to 400°F. Spray a 9x13-inch baking dish with nonstick spray.
Shred chicken. I used Rotisserie chicken but you can cook chicken in a slow cooker as well.
Heat the olive oil over medium heat in a medium skillet.
1 tbsp olive oil
Add onion to skillet and cook for 2-3 minutes, or until the onion is translucent and fragrant.
½ cup diced onion
Stir in the chicken, taco seasoning, tomatoes (fully drained), and green chiles (fully drained). Stir to combine fully. Reduce to simmer and allow to cook for 5-8 minutes.
½ lb. shredded cooked chicken, 1 oz. taco seasoning, 14.5 oz. diced tomatoes, 4.5 oz. diced green chiles
Place the taco shells in the baking dish, standing up. I was able to fit 10 taco shells in the dish by adding 2 on each side.
10 hard taco shells
Bake the taco shells for 5 minutes by themselves to allow them to crisp up. Remove from the oven.
Spoon 1 tbsp beans into the bottom of each taco shell. Top with the chicken mixture, almost to the top of each shell.
8 oz. refried beans
Sprinkle each shell generously with shredded cheese, the more the better!
2 cups shredded Mexican blend cheese
Bake for 7-10 minutes, or until cheese is fully melted and the edges of the shells are browned.
Remove from the oven and top with your favorite items such as jalapeños, sour cream, shredded lettuce, cilantro, and salsa.
sliced jalapeños, sour cream, salsa, chopped fresh cilantro, shredded lettuce