Start by preparing the vegetables and chicken. Slice the chicken breasts into thin strips, about 1/4 inch thick. Then, dice the onion and the pepper.
Get a large non-stick deep-sided pan or pot, then heat the vegetable oil over a medium-high heat. Add the chopped onions and pepper and sauté until they're softened.
Add the minced garlic and cook for another minute or two. Then add the strips of chicken and keep stirring until the chicken is browned.
Stir in the tinned tomatoes, fajita seasoning, black beans and a pinch of salt and pepper, as well as the chicken stock and give it all a good stir. (See note 1)
Then add the rinsed uncooked rice, and stir again, making sure all the ingredients are well combined. Bring to a simmer, and then cover and cook on a low heat for around 20-30 minutes, until the chicken and rice are cooked through, the liquid has evaporated and the rice is fluffy. (See note 2).
Turn off the heat, squeeze the juce of half a lime (optional) then sprinkle the grated cheddar cheese on top of the chicken and rice and pop the lid back on and leave for a few minutes are the cheese will melt from the residual heat.
Once melted, sprinkle some fresh coriander, and serve with extra toppings if desired. (See note 3).