Bring the chicken breasts and the vegetables out of the freezer to thaw.
Preheat the oven to 170 °C fan.
Pour the chicken breasts onto a tray and make a few slashes on the surface with a knife.
Rub 1 tablespoon of the peri peri seasoning all over the chicken. Leave for 15 mins.
Arrange the chicken on a baking tray and place it in the oven. Allow to bake for 20 - 25 mins.
Leave to cool. While still warm, shred by pulling apart with your hands or two forks.
While the chicken is baking, heat the oil in a saucepan under medium heat.
Add the onion and allow to brown a little with continuous stirring. Next, add the garlic and stir for around 30 secs.
Add the chopped tomatoes and ground pepper, the remaining peri-peri powder with a little salt. Cover the pan and allow to cook for around 10 mins.
Pour in the shredded chicken, sweetcorn and green peas. Stir and cover the pan. Allow to simmer for 5 mins, then remove from heat and serve.