i prefer playing the nimzo indians defence for black because it's more aggressive and leads to more complicated situations
Not the usual perspective (more often, players find the KID to be more aggressive/more complicated than the Nimzo)- but I can appreciate how everyone has different viewpoints. 
There's more complexity and aggression to the nimzo in the early / early mid game, whereas with the KID... the middlegame is where that begins. Usually my approach is to apply pressure in the early game, not wait until the midgame. This doesn't require as deep of prep, and you can hold players to very sharp, precise play this way. I don't think that's so easy to do with the KID. The KID requires *deep* prep. You often have to know very obscure lines and moves, even well into the midgame, to maintain the position, so it really leads to this immense amount of effort needed. And you get certain people who live and breath KID theory... the Fischer fans is what I call them. These people are driven by some undead zombie force. I just can't do that, I have so many other things I have to do, so... KID is a no go for me.
Taking only games from 2018 onwards on the chess tempo database it shows the usual trend that among good players (2200+ and likely the trend is also true for lower rated than that) the lower the rating the better they tend to do with the king's indian. It seems to be around the 2400 mark that a flip starts to occur (in other words it's even with the Nimzo at this point) and the Nimzo starts to produce better performances than the KID - but still completely playable at any level.
If you really want/need a win as black against d4, you don't want to be depending on a nimzo/queen's gambit/slav, you need a sharp opening. There's the King's Indian, the Benko, the Grunfeld, Benoni or the Dutch, as well as weaker offbeat openings and gambits. King's Indian leans more on the heavy theory side of things than most of those openings (other than the Grunfeld), but I think is more fun to play and more rewarding in the long run than most of them also. It's definitely not just about knowing more theory, once you are "initiated" with the theory it's full of sacrifices, ideas and thinking on your feet.
A fun thing about the King's Indian is no matter how horrible the situation can look for black in the normal mainlines where the centre is blocked, he can often out of nowhere pull off a wild tactic or a mate. Only about 10 years ago the computer used to also really hate the black side of the king's indian and then suddenly there'd be a massive swing in some lines, but of course these days the computer knows all.
In the late 1800s, one of the world's top players, the German master Louis Paulsen, adopted a unique defensive posture to the queen's pawn game which hadn't really been seen in Westernized chess: developing his king bishop to the g7 square, allowing White to get an early foothold in the center.
Over the decades, other renowned players began exploring the same setup and developing its dynamic theory, such as Euwe, Alekhine, and Najdorf.
But the defense truly entered the mainstream limelight when it became a favorite of two chess superstars: Fischer and Kasparov - both whom honed it, even further, into a fearsome weapon.
Now, in the 2020s, the defense's reputation seems to be split among players. Devotees praise it for the imbalanced, aggressive games it produces. Critics declare that engines have declawed and tamed the beast.
Where do you stand? Are you for it? Against it? Would like to know more?
Let's talk about the King's Indian ...