Add chicken thighs, sliced carrots, sliced celery, diced onion, minced garlic, diced tomatoes, drained cannellini beans, chicken broth, Italian seasoning, dried basil, and red pepper flakes to the slow cooker. Stir to combine, then spread everything into an even layer.

Cook on Low for 6-8 hours until the chicken is very tender and easily pulls apart with gentle pressure, or cook on High for 3-4 hours until tender. Keep the lid closed throughout for best heat retention.

Remove the chicken from the slow cooker and shred it with forks, then return the shredded chicken to the pot. Stir so the chicken is evenly distributed through the tomato-broth.

Set the slow cooker to High and add the ditalini or egg noodles. Cook for 20-30 minutes until tender, stirring once halfway through so noodles cook evenly.

Stir in fresh spinach and cook for 5 minutes on High until wilted and bright green. Turn off the heat after it wilts to avoid overcooking.

Season with salt and pepper to taste. Serve hot with parmesan shavings and fresh basil on top.