Pre-heat the oven to 200℃.
In a large roasting tray, add the onions and potatoes and 2 tbsp olive oil, toss all together and place in the oven for 20mins.
In a small dish, add the last 2 tbsp olive, paprika, oregano, garlic and seasoning, stir together and set aside.
Take the tin out of the oven, add the chicken, chorizo, tomatoes, courgette and peppers, drizzle over the olive oil mixtures, coat everything and place back in the oven for another 20mins.
Take the tin out of the oven, spoon over the juices from the tin over the chicken and veg, place back in the over for another 20mins until the chicken is fully cooked.
Divide between 4 plates and serve immediately. You could spoon some Romesco sauce over the top or serve with a crusty roll to mop up the last of juices at the end.