Heat a large oven-safe skillet over high heat and add the olive oil.
Sprinkle the 4 chicken breasts with the taco seasoning on both sides and sear the chicken in the pan on both sides. The chicken breasts will only need about 2 minutes per side over high heat - the idea is not to cook the chicken through, but just to develop some flavour on the outside of the chicken and in the pan. (Feel free to skip this step to save time - see recipe notes)
Turn off the heat under the pan. Remove the chicken breasts to a plate and add the chopped bell peppers, rice, and chicken stock to the pan, stirring everything together.
Add the chicken breasts back in, nestling them into the rice mixture.
Spoon the salsa over top of the chicken breasts and then top them with the shredded cheese.
Add the whole pan to the oven, uncovered, for about 25-35 minutes, or until the rice is cooked and the chicken is cooked through to an internal temperature of 165 degrees Fahrenheit or 74 degrees Celsius. (Because pans and oven temperatures vary, this can affect baking time. Use an instant-read thermometer for best results).
Once the chicken and rice are cooked through, remove the pan from the oven and serve with a sprinkling of fresh cilantro, some sliced jalapenos (optional), and even a dollop of sour cream, if desired.
To save time, skip the step of browning the chicken breasts in the pan. Simply add the raw chicken breasts into the rice mixture, top with salsa and cheese, and bake.