Looks like an injury maybe. Like it got it caught in something, or sometimes the rub them on a feeder. Another option is something tried to grab it. Hopefully it heals up.
One other option is fowl pox, but I don't think it affects the beak like that, but I'm not sure.
It probably got pecked by someone Or pecked something hard? Or was pecking at something & got it's beak wedged? No clue as to how that happened, doubt it "scratched" it's self. Looks like it's scabbing over, if you can try cleaning the area by the nostrils but don't get any in. Keep it clean & think it'll be ok on it's own.