Season chicken with salt, pepper, oregano, and basil.
Heat olive oil in a large skillet over medium-high heat.
Add chicken breasts and cook for 5-7 minutes per side.
Transfer cooked chicken to a plate and cover with foil.
In the same skillet, melt butter over medium heat.
Add mushrooms, onions, and bell peppers.
Sauté vegetables for 5 minutes until tender.
Add minced garlic and cook for 1-2 more minutes.
Pour Marsala wine into the skillet.
Scrape up browned bits and let the wine simmer 2 minutes.
Add chicken broth and heavy cream. Stir well to combine.
Return chicken to the skillet.
Spoon sauce and vegetables over the chicken.
Simmer for 5 minutes to blend the flavors.
Transfer chicken and sauce to a serving platter.
Spoon extra sauce and vegetables on top.
Serve immediately and enjoy your Chicken Sinatra!