In your slow cooker, place the boneless skinless chicken breasts and pour in the canned petite diced tomatoes along with the balsamic vinegar. Add the large sweet onion, minced garlic, and homemade Italian seasoning for an aromatic kick. Gently stir the ingredients until the chicken is well coated with the mixture, ensuring even flavor distribution.

Cover your slow cooker with its lid tightly, and set it to cook on low for 5 hours. This low and slow process allows the flavors to meld beautifully, resulting in succulent chicken and a rich sauce.

After the 5 hours are up, carefully remove the lid from the slow cooker. Using two forks, shred the tender chicken right in the pot, mixing it with the sauce for maximum flavor integration.

Return the shredded chicken to the slow cooker along with the drained canned stems and pieces mushrooms. Stir gently to incorporate them into the mixture. Cover the pot again and let it rest for about 10 minutes.

While the mixture rests, cook your choice of pasta according to package instructions until al dente. Drain the pasta and serve topped with the flavorful shredded chicken and sauce, finishing with a sprinkle of Parmesan cheese.