In foil lined 9x13 pan, spread broccoli evenly; Place chicken pieces on broccoli. Spoon and spread soup evenly and thickly. Slice onion and put chunks between chicken pieces. Season to taste with salt & pepper (maybe a little lemon pepper or something you favor.)
Bake with foil cover at 325°F for 1.5 hr.
Remove and put cheese (slices or shredded) on top of chicken. Put back in oven, uncovered, for another 10 minutes at 350°F or until cheese starts to brown. Serve from the baking pan.