In a large pot, cook pasta according to package instructions for al dente. Add broccoli to pasta in the last three minutes of cooking. Drain and return to pan and add chopped dried tomatoes.
In a large skillet or large frying pan, melt butter over medium heat.
Add chicken, onions, seasonings, and red pepper flakes to pan and cook until chicken isthoroughly cooked and onions are tender.
Sprinkle flour over chicken mixture. stir, and cook for 1-2 additional minutes.
Pour milk and chicken broth into skillet, stir and bring to a boil over medium heat.
Once sauce has thickened a bit, add cheese and stir until combined.
Pour mixture into the pasta and broccoli. Stir to combine.
Enjoy with a side salad or crusty bread with butter or garlic bread.