Heat oil in large skillet over medium heat. Saute chicken with garlic and salt and pepper until lightly browned. Add onion and cook two minutes. Add broccoli. Toss with chicken and cook for one minute. Add 1/4 cup parmesan cheese.

Cook pasta according to box. Drain, do not rinse. Toss ziti with butter. Add to chicken and broccoli. Add remaining parmesan cheese. Toss and serve.