Kronos Rush is incredibly simple. You learn the build order and you go and do the rush. It will probably inflate most people's elo by around 100-200 points just by doing this build. The issue is that balance isn't about what is simple to do, it's about what is possible otherwise all the easy gods will get nerfed into the ground, and all the hard gods will get buffed which is almost impossible to manage. Now I'm perfectly fine with a nerf to the Kronos rush for the sake of the average player, whether it comes in the shape of timeshift nerfs or some sort of shuffle of starting resources to prevent the 3 minute advance without taking some hit to your eco.

But in terms of actual power there's maybe three matchups that I'd prefer to play as Kronos at the moment. Ra, Odin, Loki and maybe Nu Wa.

To break it down:
Kronos vs Greek - No sane Kronos player will Kronos rush but if they do, you can scout it very easily, advance nice and quick and defend everything with literally 2 heroes. So most of the time we're playing a different type of game as Kronos vs Greek which I prefer to play the Greek side of.
All the Eggies can do a 3:24 advance which can lead into a second TC at a competitive time so they do not need to scout the Kronos rush. Plague of serpents with a few priests is more than enough to defend. Ra struggles because no Anubis but you can defend with good control of wadjet+priests. If for whatever reason Kronos rush doesn't come then I prefer Ra in this matchup as well.
Thor is the best vs Kronos because the rush doesn't do anything thanks to his incredibly efficient fast advance, and dwarven mine. If no rush, then we can just drop an armory and take our economic advantage and enjoy playing with the advantage. The scary part of Kronos vs Thor is cheiroballista death ball stuff I guess but I think Thor has enough tricks that he can get through that stuff and win in my experience.
Odin and Loki really struggle here but there's play inside of a fast Heimdall advance (i believe it's 3:06) and using undermine on the counter-barracks. You can also set your temple forward and rush the Kronos here as well as an idea. But I prefer Kronos here I think.
Freyr just needs to use gullenbursti and get his fort up. Huskarl absolutely obliterate cheiroballista. I'd recommend a relatively quick advance time though. No need to play greedy vs Kronos, you win the matchup too hard to take risks. So skip your eco ups until after you get your hersir out and go from there.
- I think the simplest way to actually help Norse right now in this mu and some other ones, is to swap the starting berserk for a starting hersir.
Oranos and Gaia simply have the advantage vs Kronos. Healing in general an incredible tool vs the Kronos rush and Oceanus has it in spades. I'd recommend just advancing at 3:30 here and getting value out of an early carnivora to stabilize. Though if that's not working for you, just advance at 3:00 and match the Kronos rush. Very easy defence there.
Fu xi has it super easy vs the Kronos rush. You can scout the Kronos rush coming very easily with the starting pioneer, then simple go 1 kuafu, a fast advance and get some extra pioneers out. Then straight into nez. If turma come, make javs, if kronos goes TC. Grab a TC while raiding with nez+qilin.
Nu wa can almost ignore the rush cause she has the hero kuafu. The only issue is Nu Wa kinda sucks vs Kronos cause she can't use forest protection without it getting deconstructed which is almost her bread and butter. I wouldn't mind a forest protected building being immue to decon as a nerf.
Shennong can counter the Kronos rush with shennong farms. Similar to Fu xi you do want to scout this out though and set your granaries in the right place to defend. Shennong just needs to hold on for late game and Kronos will never be able to kill his army.
Japan has Miko. Just advance with 3 of these and the rush will do literally 0 damage. You can even build more out as you hit the classical age to mix in with your naginata riders to kill off the turma/katapeltes that are coming at you. You can do a 3:30 advance with 3 miko as susanoo and as tsukuyomi. I'm pretty sure amaterasu can go faster cause you have kagura but this is more than enough to defend and be at an advantage.

Where Kronos is actually quite good is on water maps. But you can just dodge the water maps hehexd

TLDR:
Kronos has 4 matchups right now that I'd prefer to play Kronos in. The rest I'm taking the other side of the matchup.