Add bell pepper and onion to the pan; cook, stirring occasionally, until tender, about 5 minutes. Stir in garlic, oregano and crushed red pepper; cook, stirring, until fragrant, about 1 minute. Add wine and cook, scraping up any browned bits, until most of the wine is reduced, about 1 minute. Add tomatoes and the chicken. Reduce heat to maintain a simmer, cover and cook until the chicken is tender and cooked through, about 15 minutes.