A tl;dr on how this works: people borrow the Yen because Japanese interest rates are so low, then they buy stuff that they think will outperform (NVDA, etc.). The Bank of Japan did a surprise hike last week, which threatens the outlook of Yen interest rates continuing to be low. Therefore this trade is being unwound.
...and because of the extreme gains in those stocks (like NVDA) those are the ones getting sold to facilitate the unwinding. This is the "tails we lose" part. They still win of course.