Heat the canola oil in a large Dutch oven or a heavy-bottomed soup pot over medium-high heat.
Add the carrots, celery, and onion to the pot and sauté until they begin to soften and become fragrant.
Stir in the Italian seasoning, salt, minced garlic, and black pepper, cooking for another minute until aromatic.
Pour in the chicken broth and bring the mixture to a gentle boil.
Carefully add the boneless, skinless chicken breasts to the broth and reduce heat to low, simmering until the chicken is cooked through.
Remove the chicken breasts, shred them using two forks, and return the meat to the pot.
Add the cheese tortellini to the simmering broth and cook according to the package directions until tender.
Stir in the fresh chopped spinach and cook just until wilted before serving.