I want to do this too, but I have Instagram scammers that already DM my friends and family trying to ask them for money. I worry that nuking accounts everywhere would invite more scammers. 

 BY HAVING THOSE OTHER ACCOUNTS SCAMMERS PREY ON THE POSSIBILITY IT IS YOU

BY BEING LOUD & PROUD ABOUT NOSTR ONLY IT MAKES IT CLEAR THAT ANYTHING OUTSIDE NOSTR IS AUTOMATICALLY SCAM