Heat olive oil in a large soup pot over medium heat.
Sauté diced onion and minced garlic for 3-4 minutes until fragrant.
Stir in diced tomatoes and Italian seasoning; let simmer for 3 minutes.
Add chicken broth and bring to a gentle boil. Reduce heat and simmer for 10 minutes.
Add shredded chicken and cook for another 5 minutes.
Stir in heavy cream and simmer until heated through.
Gradually add Parmesan cheese, stirring until melted and smooth.
Season with salt and pepper. Serve hot topped with parsley and extra cheese.