Cook the spaghetti in a pot of boiling salted water for 10 minutes.
Heat the oil in a large skillet.
Brown the bell pepper, mushrooms, onion, and garlic in the skillet and sauté for 5 minutes, until the vegetables are soft and the chicken is no longer pink.
Melt the butter in a pan and stir in the flour.
Keep stirring until a paste is created.
Slowly pour in the broth, half-and-half, and wine while continuously stirring.
Season the sauce with pepper, oregano, and thyme.
Stir in the Italian cheese blend and stir for 5 minutes, until the cheese is melted.
Add the browned vegetables and simmer for 5 minutes.