Add onions and peppers to a large bowl with salt & pepper, 1/4 cup olive oil, and 1/4 cup white wine. Coat well. Distribute evenly in a parchment paper-lined baking pan. Set aside.
Repeat with potatoes and rosemary leaves. Do the same for the sausage, then the chicken. Add remaining rosemary sprigs as you like.
Bake at 375° for 60-75 minutes until chicken is cooked to 165° and golden brown. Plate and serve.