Season chicken pieces with salt and pepper. Heat olive oil in the soup pot over medium heat. Sear the chicken until lightly golden on the outside (about 4-5 minutes). Remove and set aside.

In the same pot, add more olive oil if needed. Sauté the onions until translucent (about 3 minutes). Add garlic, oregano, and red pepper flakes, cooking until fragrant (1 minute).

Stir in the diced tomatoes and chicken broth, scraping the bottom of the pot to release any browned bits. Bring to a gentle simmer.

Lower the heat to medium-low and stir in the heavy cream. Return the seared chicken pieces to the pot.

Stir in orzo pasta and simmer until the pasta is tender (about 8-10 minutes). Add the sun-dried tomatoes, spinach, and Parmesan cheese, stirring until the spinach wilts and the cheese melts.

Season with additional salt or pepper if necessary.

Ladle the soup into bowls. Garnish with fresh basil leaves and extra Parmesan cheese.