In a large pot, heat the olive oil over medium heat. Add the diced chicken thighs and cook until browned on all sides, about 5-7 minutes. Remove the chicken from the pot and set aside.
In the same pot, add the diced onion and sauté for 3-4 minutes until translucent. Add the minced garlic and Italian seasoning, stirring for an additional minute until fragrant.
Toss in the halved cherry tomatoes and cook for another 2 minutes, allowing them to soften.
Pour in the chicken broth and bring to a simmer.
Stir in the orzo pasta, then return the browned chicken to the pot. Cover and cook for 8-10 minutes, stirring occasionally, until the pasta is al dente and has absorbed most of the liquid.
Add the chopped spinach, heavy cream, and grated Parmesan cheese to the pot, stirring until the spinach wilts and the cheese melts into a creamy sauce.