Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius) and lightly grease a 9x13 inch baking dish.
Distribute the uncooked long-grain rice evenly across the bottom of the baking dish.
In a large mixing bowl, combine the cubed chicken, bell peppers, and onions.
Add olive oil, fajita seasoning, and salt to the bowl and toss until the chicken and vegetables are thoroughly coated.
Layer the chicken and vegetable mixture evenly over the rice in the baking dish.
Pour the chicken broth over the entire mixture, ensuring all rice grains are submerged in liquid.
Seal the dish tightly with aluminum foil to ensure steam is trapped for proper rice hydration.
Bake in the preheated oven for 35 minutes.
Remove the foil, sprinkle the shredded cheese over the top, and return to the oven uncovered.
Bake for an additional 10 minutes or until the liquid is fully absorbed, the rice is tender, and the cheese is melted and bubbly.
Remove from the oven and allow the casserole to rest for 5 minutes before serving to stabilize the texture.