Heat oil in a large dutch oven or soup pot over medium-high heat.
Add vegetables and cook, stirring often, until onions are softened, about 4-5 minutes.
Add Italian seasoning, salt, garlic and pepper and cook 1 minute.
Add chicken broth and chicken breasts and bring to a simmer over high heat. Reduce heat to medium-low, cover, and simmer until chicken is cooked through (10-14 minutes, depending on the size of your chicken breasts).
When chicken is cooked and vegetables are tender, remove chicken breasts to shred or chop. Stir in cheese tortellini and spinach while you shred the chicken.
Stir chicken back into soup and serve.
