Originally Posted by Agneisse

(Potential) problem will be with immigration queues at NRT.

If you want a later flight, the cheapest same-day backup option is the last flight with either Peach (8:45pm) or Jetstar (7:45pm) NRT-KIX flights once they release their Summer 2024 (= April and beyond) timetables. This will be a lot cheaper than the solution of NRT-HND taxi + a last minute flight although perhaps not sufficiently cheaper than the combination of Narita Express + Shinkansen to want to deal with a LCC.