01 - Add diced tomatoes, tomato pasta sauce, minced garlic, salt, Italian seasoning, dried basil, and black pepper to a 3- to 6-quart slow cooker. Stir thoroughly to blend the flavors.
02 - Whisk together evaporated milk or heavy cream with corn starch until fully smooth. Pour into the slow cooker and stir to incorporate with the base sauce.
03 - Arrange boneless skinless chicken breasts in the slow cooker, submerging them in the tomato mixture.
04 - Cover and cook on low heat for 3 to 5 hours, or until a meat thermometer inserted into the thickest part of the chicken reads 165°F (75°C). Cooking duration depends on your slow cooker model.
05 - Gently stir in finely chopped fresh basil just before serving. Serve warm, optionally over pasta, rice, or alongside a fresh salad or steamed vegetables.