Turn slow cooker onto high heat and melt butter. Whisk in flour and let cook for 5 minutes, stirring frequently. Add in water, garlic salt, onion powder, and frozen broccoli. Let cook on medium heat for 2-3 hours on high, or 4-5 hours on low, stirring occasionally. Stir in heavy cream.
Add the chicken, and cook for an hour. Test chicken for doneness, and add pasta during last 20 minutes of cooking time. Stir in 2 cups cheese until melty. Mix up crushed ritz and remaining half cup of cheese, and sprinkle over the top. Heat until the cheese is melted.
Notes
Adjust cooking times according to your specific slow cooker. Test chicken doneness by cutting a piece in half and if there is no pink its done! Use rotisserie chicken for easier prep. Add in at the very end with the pasta. Low quality pasta or egg noodles will take much less time to cook than high quality pasta.