Heat a generous amount of olive oil in a large skillet or paella pan over medium heat. Add the diced chicken and sliced chorizo to the pan and cook until browned. Remove the meat from the pan and set aside.
In the same pan, add the chopped onion, minced garlic, and sliced bell peppers. Cook until the vegetables are soft and the onions are translucent.
Add the paella rice to the pan and stir well, ensuring each grain is coated in the oil and vegetable mixture. Cook for a few minutes until the rice becomes slightly translucent.
Add the chicken stock, saffron, and a pinch of salt and pepper to the pan. Stir well and bring the mixture to a boil. Once boiling, reduce the heat to low and let the mixture simmer for about 20 minutes, or until the rice is cooked and has absorbed most of the liquid.
Add the cooked chicken and chorizo back into the pan, along with the frozen peas. Stir well and cook for a further 5-10 minutes, until everything is heated through.
Serve the paella hot, garnished with freshly chopped parsley and lemon wedges on the side.