Definitely need tortilla chips and salsa for snacking, alternatively Ruffles and french onion dip or spinach dip for those that don't like salsa. For those that insist on pretending to be healthy this day, a tray of veggies (such as carrots and celery) to dip into ranch dressing.
As for an actual meal...well, really you just snack all day long on crap, there is usually no actual meal. But if there is, perhaps some homemade slow-cooker chili, wings, nachos, or of course pizza. If you need specific instructions on how to prepare these dishes the "American way," I'm sure we can provide help.
Basically, think fatty, greasy, messy, very easy to prepare. Something you can eat with your hands! No place settings or even a table is needed, just your couch and a paper plate full of yum. Beverages should include beer or margaritas. Strawberry and grape soda for the non-alcoholics.
Mexican food is very popular on Superbowl Sunday (well actually it's popular all the time where I live). You may need some sort of bean dip, guacamole, quesadillas. It's really up to you!