Start by preheating a 3-quart slow cooker on the low setting while you prepare the ingredients. Add the green peppers, onions, and carrots to the bottom of the slow cooker.
Add the marinara sauce and wine. Cover and cook on low for 2 hours. If you don't have a marinara sauce you can use crushed tomatoes and add garlic and Italian seasonings.
After 2 hours, microwave the precooked chicken to heat and add to the slow cooker. Y Add the mushrooms and olives. Cover and cook on high for another hour.