Comment by grishka

It's been a few hours. These particular bots have completely stopped. There are still some bot-looking requests in the log, with a newer-version Chrome UA on both Mac and Windows, but there aren't nearly as many of them.

Config snippet for anyone interested:

    if ($http_user_agent ~* "Chrome/\d{2,3}\.\d+\.\d{2,}\.\d{2,}") {
      set $block 1;
    }
    if ($http_accept_language = "") {
      set $block "${block}1";
    }
    if ($block = "11") {
      return 403;
    }