I understand that CC'ing her works, which is why I don't believe she is OP. That being said in top lane not to many champions have a edge on her. Your thoughts in the lane?
Well, I main Nid top lane and I find the matchup to be one of the most fun in the game, honestly. If you fuck up, she can kill you sure, but you have definite advantage and outplay potential. As Nasus I just start cloth 5, and farm my Q. Once i have wardens mail I just flat out ignore her.
For actual hard counters, look no further than Garen. Tanky as balls, can't die to her, can't gank him, he shreds her from level 1. Or Renekton. Bit of a harder lane bully early on, but he falls off, especially damage wise, but he counters her harder than Garen, at least in lane.
Ryze can shit on her pretty bad too, if he's careful. As long as he avoids being cheesed at level 2, he can poke and deny her any potential to trade back damage. Hell, even ANOTHER melee like jax can beat her too while outscaling hard.
Honestly, Riven isn't that big of a deal anymore. Any melee that goes top is far too tanky for her to kill, and any Range, is well, ranged so they can poke and kite her back. She still snowballs incredibly hard but she requires a bit more skill to snowball to begin with in my opinion, long past are the days where running up and Q auting you three times + ignite would kill you.