Upvote:4
I'm going to guess that you're not actually flying Continental as they haven't existed for over 3 years. Odds are you're actually flying United Airlines which is who they merged with.
United Airlines flights depart from either Terminal C or Terminal A. For this flight, given it's on a regional jet, it's most likely Terminal A. United do NOT have check-in facilities in terminal B, so you will need to catch the train to terminal A to check-in, and you must have completed check-in/bag drop by 45 minutes before your flight departs. Thus you would have 10 minutes to get off your flight, go through immigration, collect your bag, go through customs, catch the train, and then check-in. I don't think I need to tell you this isn't possible.
To answer your specific questions :
1) No. It's not possible to make this connection with luggage.
2) If you attempt to leave your bag it will be confiscated by US Customs. It may be possible to get it back, but it will be a difficult and likely expensive process. Even then, the chances of you getting through immigration/customs/check-in/security and then catching your flight in 55 minutes (keeping in mind that technically you need to board 15 mins before the departure, so it's really 40 minutes) is still extremely close to zero. It took me ~25 mins to get through security alone at Newark last week, and I have priority access...
3) United has a "flat tire" rule that if you arrive at the check-in counter within 2 hours after your flight departs they will attempt to put you on a later flight for no charge. Given that you are on the last flight of the day to Nashville, they may or may not do this for you. Technically they have absolutely no obligation to you given that you are not on a single ticket.