Coat chicken pieces with flour, salt, and pepper.
Heat oil in a large skillet and brown the chicken on all sides. Remove and set aside.
In the same skillet, sauté chopped onion, green bell pepper, and garlic until soft.
Add diced tomatoes, white wine, oregano, and mushrooms. Stir well.
Return chicken to the pan, cover, and simmer for 35-40 minutes until cooked through.
Season with salt and pepper to taste.
Garnish with fresh basil leaves before serving.