We actually already have support for that with the broadcast-events command but I improved it a bit just now. Just make a json file with an array of nostr events and execute this command:
nostr-tool -r wss://nostr.oxtr.dev broadcast-events -f events.json
I also added a new "custom-event" command where you can specify an arbitrary kind number, content and arbitrary tags. You'll need to be on latest main version to use this though. I'll try to do a release by the end of tomorrow, just want to get some more stuff into the 0.4.0 release
