Add the chicken to a bowl, along with all of the peri-peri chicken ingredients except the oil. Mix well to combine.
Place a pan over medium-high heat, add spray oil and the chicken, and cook for 2 ½ minutes on each side, until golden and cooked through. Add a splash more Nando's peri-peri sauce right at the end, if desired. Remove, rest, and slice into strips.
In a saucepan over medium-high heat, melt the butter. Add the onion and red bell pepper and cook for 3 minutes, mixing regularly. Add the garlic and tomato paste and cook for a further 2 minutes.
Add the washed basmati rice and stir to coat in the pan, toasting for 1 minute. Add the chicken stock, smoked paprika, turmeric, chilli powder, and oregano. Mix well, bring to a boil, then reduce the heat to low, cover, and cook for 12 minutes.
Turn off the heat and leave the lid on for 4 minutes. Remove the lid, add the peas and coriander, and fluff with a fork.
Portion the spicy rice into six meal prep containers. Top with the sliced chicken and extra Nando's sauce, if using. Garnish with coriander.