Add the chicken to the skillet and cook until browned, approximately 3-4 minutes. Flip the chicken over and brown on the opposite side, approximately 3 minutes. Remove from the pan. Set aside.
Layer the onions, peppers, mushrooms and garlic in the slow cooker.
Arrange the chicken breasts on top of the vegetables.
Pour the wine, tomatoes, tomato sauce, butter and seasoning over the chicken. Sprinkle with salt and pepper.
Cover and cook on high for 3-4 hours or low for 6-7 hours.
Remove the chicken. Stir the vegetables and fresh herbs to combine.
Serve the chicken with the sauce and vegetables over pasta or rice, if desired.
Video
Notes
Chicken Cacciatore can be made up to 4 days in advance and stored in the refrigerator in an airtight container.