Many options.
Winterfell holds but at great cost (such death, much angst). Night King killed along with Jon (who's also been killed before) who assumes power over the deadites and uses that as a final bludgeon against King's Landing. Jon dies/goes out quietly leaving his Aunt to take over as the Deadites crumble into snowflakes.
Winterfell falls and now it's a case of all hands on deck (such death, much angst). Heroics everywhere, dragons, magic, and generally NOT GOING QUIETLY INTO THE NIGHT (much death, lots of angst).
Option 3 - After much death, great angst, huge CGI - the Night King accepts that finally the Kingdoms have someone worthy to lead them and gives up willingly with his army collapsing as their duty has been done. This also works if the sense of betrayal is established and forgiven amongst the participants. Jamie, Night King, Dany, etc.