Heat a large dutch oven coated with cooking spray over medium high heat and saute the onions and garlic 1 minute or until fragrant. Add the chicken and cook until lightly browned.
Stir in the next five ingredients (pasta through garlic powder). Making sure the pasta is fully submerged, bring the broth to a full boil, and then reduce heat to low boil. Cook 10 to 12 minutes or until pasta is cooked and most of the water has been absorbed.
Using a whisk, stir in the cream cheese and cheddar until melted then fold in the broccoli and serve.