Pre-heat oven to 350 degrees. In a large bowl, mix alfredo, chicken, broccoli, and cheeses. Spoon mixture into pasta shells. Grease 13 x 9 baking dish with butter or cooking spray. Evenly spread spaghetti sauce on bottom of baking dish. Arrange shells in baking pan. Cover with foil and bake 35 minutes until heated thru. **Notes** Remember that the noodles need to be cooked prior to stuffing. I usually like cooking them 1-2 minutes under what the package says, that way they will fully cook when baking in the oven! This recipe can easily be altered to your liking. One easy filling addition -- chopped cooked bacon! Tip #1: You can prep all items in advance, right up to the point of baking. Keep covered in refrigerator until you are ready to bake. Tip #2: Own a cookie scoop? Use your cookie scoop to easily stuff your shells! Tip #3: You can freeze this! Just pre-assemble all the noodles with the filling. Freeze stuffed noodles without the red sauce. Then, thaw when ready to bake!