Indeed
The community created many… many false myths that are considered holy for some 
Most of the descriptions about N’Zoth came from Xal’athath (and keep in mind she is not that… reliable)
“Another seed of corruption planted in death. An unquiet spirit will wander in anger and grow in pain. Easy prey for the God of the Deep” - when refered Elerethe Renferal
Not much about it, a spirit in pain and full of anger is easy prey for N’Zoth. But to be honest I think for everyone else
“Xavius, running from one master to the next, scrambling for power, yet defeated again and again. The God of the Deep picks a poor champion? Or, is there something else at play?” - when facing Xavius
Again, not really tells us much. Either he picked poorly - not a good point for a great deciever - or used Xavius, like everyone elese
“The God of the Deep writhes in his prison, breaking free ever so slowly. You should hurry and defeat the fallen titan… there are greater battles yet to fight.” - in Val’sharah
And again? Nothing. A freed Old God is a problem the Titans had difficulity to handle; then again except one, the Titans personally not really interfered just their Titan-Forged servants and their creations. Pre-programmed barely freewilled constructs against the incarnations of Darkness… not a surprise and not really talks about N’Zoth power or personality
“It was here in ages past that the God of the Deep lost a great battle to the God of Seven Heads. But as was so often the case even defeat ultimately worked in N’zoth’s favor.” - at the Broken Shore
Now maybe, but only maybe this could be interpreted as N’Zoth usually had contingency plans.
A thing usually true for anyone who have more than two braincell and read the Evil Overlord List…
“It is ironic that the weakest of us may be the ultimate victor. C’Thun, Yogg-Saron, Y’Shaarj, and… well. Only one would remain to consume the world, that was always meant to be.” - in the Hall of Glory in the Halls of Valor
Now this is a strange one. We only could assume she was talking about N’Zoth. Considering she was torn apart and according to this, she considered herself equal to the other Old Gods. The place is interesting too that triggers this, the Hall of Glory in the Halls of Valor where N’Zoth… well… not really had a presence. While Xal’atath was there, in the hands of the Priest…
BUT if she was refering to N’Zoth? Then she just only said, N’Zoth was the weakest and it is ironic N’Zoth potentially could be the victor at the end.
Not expected.
Ironic
Aside that, Chronicles tells us N’Zoth was the first of the Old Gods to be defeated and sealed in an underground prison
And after that? N’Zoth next big move was with Azshara and it was, a “I have watched you, I know you want power, yadda yadda yadda… serve me and have power and… what? No? Why? Ohhh… yes, because you are a Queeen. Okay… you have all the cards, here, power, now get to work!” - except she never served N’Zoth, and came out of the bargain the better out the two; she recieved the whole ocean as her domain and her people survived, while N’Zoth… gain a minor influence and tought them Void and Shadow and… made them stronger? The Naga never really were N’Zoth’s army, they were Azshara’s people and army and empire… and Azshara serves ony Azshara. Even to “free” N’Zoth was a trick from her part
The corruption of Andrassil and the Dream, creating the Nightmare wasn’t really N’Zoth’s work, it was Yogg-Saron who gain acces to it and shared it with the others. It was a joint effort.
When the Cataclysm came C’Thun and Yogg-Saron was already “defeated” - as we later learned, beaten back to their dormant state, not killed - and N’Zoth was the only one active, but not really because of his strategies and brillant mind… but because no one really knew N’Zoth even existed and where the Fel was imprisoned. N’Zoth was “free” to do whatever wants untill like the others exposed itself and recieved a slap on the tentacle
When it comes to corruption? N’Zoth corrupted Death Wing - allegedly. In the War of the Ancients Trilogy, “the Old Gods” were collectively implied to be responsible for Deathwing’s corruption. Not just N’Zoth
It was Yogg-Saron who corrupted the Titanic watchers, and planted the Curse of Flesh in the Forge of Wills (and most of the sources claims the Curse of Flesh was Yogg-Saron’s creation
And… thats all
Nothing, literally nothing supports the myth, N’Zoth was a briliant mind and tactican, a clever schemer, the unholy child of Professor Moriarty, Sherlock Holmes and Grand Andmiral Thrawn
N’Zoth was just a weakest of the four (five… or six. Y’Shaarj, N’Zoth, C’Thun, Yogg-Saron, by her own account, Xal’atath… but in the Forbidden Shores, in the book The Old Gods and the Ordering of Azeroth it is mentioned: "The Pantheon shattered the Old Gods’ citadels and chained the five evil gods far beneath the surface of the world. " - except Y’Shaarj was never chained, Aman’Thul ripped it from Azeroth and tore it apart. And G’Huun never had a citadel, nor even existed at the time (or could be considered an Old God). So… by the lates canon sources we had six Old Gods! ) Old Gods who was lucky no one even knew it existed thus had the opportunity to command the Old God forces during the Cataclysm… and as soon as made its moves, died - really, as basically expected.