Bring a large pot of water to a boil. Add rotini and cook until tender. Drain and set aside.
Heat oil or butter in a large skillet over medium heat. Add chicken and cook until fully cooked through.
Add minced garlic and Italian seasoning and cook for about 30 seconds, just until fragrant.
Pour in milk and simmer for 2-3 minutes, just until warmed and slightly thickened.
Stir in parmesan cheese until melted and combined.
Add frozen broccoli to the skillet and cook 3-5 minutes, stirring, until heated through.
Add cooked pasta and toss until everything is evenly coated.