In a frypan, sauté the mushrooms, onion and capsicum.
Add the chicken pieces, cooking for 5-7 minutes until chicken is browned.
While the chicken is cooking, start cooking the spaghetti in a pot in lots of salted water.
Back at the frypan, add the diced tomatoes, pureed tomatoes, cayenne pepper, chilli powder and garlic powder. Simmer for 10 minutes, stirring occasionally.