Who's a REALLY hard counter to Irelia
By really hard I mean REALLY FREAKIN HARD
As in hard enough to the point it's possible for a gold player to actually win or go even in lane and still do well against her later in the game if she gets ahead
Why? I've got tournament game against a Diamond 2 Irelia/Riven main tomorrow. Scouting shows 300+ Irelia games this season and 400+ Riven games
The guy's Riven? Couldn't care less about, my team's decided to instaban her every game but leave Irelia open to try to shut down their ADC's champ pool to make sure our ADC wins his lane
I'm Gold, former Plat...I've always struggled vs Irelia anyway. Lose and she snowballs. Win lane, she gets fed on cleanup kills unless literally every lane snowballs to hell
Even when playing "counters" like Volibear or Darius I can win lane but be useless against her lategame as she tears me apart despite my tank stats. Nasus? In Soloque maybe I can do that. Against a coordinated team, I'll never get the farm needed to finally shut her down. And this is against Irelias my skill level
A 300+ game Irelia MAIN 2 rank above me? Jesus...what do?

to be good picks. A lot of them depends on how your team wants to win though (siege, splitpush etc.).
Also yes that is a nunu. You won't scale well, but it buffs your adc which it sounds like is your best player and it demolishes irelia in lane very easily as long as you dont overextend and get ganked. Just build sunfire+iceborn and snowball her all the time and you should be fine.
Also.... prepare for her to tilt and flame you so if this is between friends don't do it.