Preheat your oven to 375°F (190°C) and prepare a 9x13-inch baking dish with nonstick cooking spray.
In a large skillet, melt the butter over medium heat. Add the diced onion, diced poblano pepper, and diced red bell pepper to the skillet and saute until they are tender, about 3-4 minutes.
Add the shredded chicken to the skillet and mix with the sauteed vegetables.
Add in the taco seasoning, green chilies, and chicken broth and mix thoroughly. Allow the mixture to simmer for 5-7 minutes, stirring occasionally, until everything is well combined and heated through.
Place the hard shell tacos in the baking dish, standing them up so they do not fall.
Evenly distribute the chicken mixture into each taco shell. Sprinkle the shredded cheese generously over the top of each taco.
Place the baking dish in the oven and bake for about 10-12 minutes, or until the cheese is melted and bubbly.
Remove the tacos from the oven and allow them to cool slightly.
Serve the baked tacos with your favorite toppings such as salsa, sliced jalapenos, diced red onion, taco sauce, sour cream, or fresh cilantro. Enjoy!