NFL Rookie Mekhi Becton Cops Massive 'Big Ticket' Chain, $400k Value!

What does a dude nicknamed "Big Ticket" get for a chain?? How about A BIG ASS TICKET!! TMZ Sports has learned ... New York Jets rookie Mekhi Becton is the proud new owner of a piece that is as big as his 6'7", 360-lb. frame ... copping a huge…