Heat 2 tsp olive oil in a large dutch oven or pot. Saute the onions and chicken pieces until onions are soft and tender and the chicken has browned on all sides.
Add the garlic, red pepper flakes and crushed fennel seeds, stir until fragrant (about 1 minute).
Add the chicken broth, diced tomatoes, tomato sauce, tomato paste, Italian Seasoning and noodles. Bring to a boil then reduce heat to a simmer. Cook until the noodles are tender, stirring occasionally. Finally add the parmesan cheese and stir until melted. Serve the soup with additional parmesan cheese on top and fresh basil if desired.