So I never realized this till now, but my Master Chief Collection didn’t come with nightfall, had it new on disk, then digitally downloaded after it broke. It said it would come with it, but it didn’t.
There should have been a code for Nightfall included with your disc, some retailers may have printed the code on your receipt. If you load up the Halo Channel you should be able to watch it
To be fair, Nightfall is pretty s**t so it’s no great loss. It’s a shame too, cause Forward Until Dawn was surprising good.