Heat olive oil in a large skillet over medium heat.
Season cubed chicken with salt, pepper, and Italian seasoning, then add to the skillet. Cook until browned and fully cooked. Remove and set aside.
In the same skillet, melt butter. Add garlic and sauté for 1 minute.
Whisk in flour and cook for 1 minute until golden.
Gradually whisk in heavy cream and chicken broth. Bring to a simmer and cook until thickened, about 3–4 minutes.
Stir in Parmesan cheese until melted and smooth.
Add the cooked tortellini, chicken, and broccoli. Toss to coat evenly in the sauce.
Garnish with chopped parsley if desired. Serve warm.