Place this clip as the immediate reaction beat after the odd Japan line in your edit, then follow it with the huh reaction for confusion and Nelson's Ha-Ha! for the mocking payoff, in that order, before cutting back to normal dialogue.
About this sound
This is a short 2.5-second voice clip of someone declaring that Japan is so funny, delivered as a flat, out-of-nowhere reaction line. It feels awkwardly amused and a little bewildered, like a punchline with no setup, which makes the statement land as unintentionally hilarious rather than as a real travel opinion or review.