now accepts human-readable date inputs to --ts, --since and --until:

~> nak event -ts 'two weeks ago' -c 'I bet Trump will dodge a bullet one of these days' ~> nak req -k 1 --since 'a month ago' --until 'July 1st'

Also it will automatically use a private key from NOSTR_PRIVATE_KEY if that is available in your environment, thanks to @cloud fodder and @mattn.