you might have to follow the bridge first. nostr:npub1pqr3g2gk3vsnrqk9kwfqqcxc6d5cwjr0hyc0nlzz9py5nf92vd9sn02sck

Then, if the account you're looking for has followed the bridge on BlueSky, their Fediverse username would be @montyglu.bsky.social@bsky.brid.gy