Cook the tortellini according to package instructions. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Add diced chicken, season with salt, pepper, and Italian seasoning, and cook until golden and fully cooked. Remove and set aside.
In the same skillet, add minced garlic and sauté for 30 seconds until fragrant.
Add chicken broth and heavy cream. Stir and bring to a simmer.
Stir in Parmesan cheese, red pepper flakes (if using), and butter. Cook until the sauce thickens slightly.
Add spinach and cook until wilted, about 1-2 minutes.
Return the cooked chicken and tortellini to the skillet. Toss everything together until well coated in the sauce.
Serve warm, optionally topped with extra Parmesan and cracked black pepper.
