fast bite norscan leaders and vasalize them all

Raid because its free. First thing is to vasallize norsca and demand money from them. Make marauders because they are cheap and strong. Warriors are late game stuff so dont be afraid to use a lot of marauders. And raid!

Get rid of the elite troops which aren't cost effective in the early game; you want your army as wide as possible so fill it with marauders/horsemen.

You also might want to keep your chaos sorceror for block army, since you don't have ambush and will likely be chasing people around the map.

Chaos have one of the easiest starts in SFO, Norscan's have the worst fortifications, and you can easily grind your gold, levels on them. So consider sailing to the other side of norsca away from the human and dwarve settlements.

While this might be more of a high risk, high reward aggressive business management gameplan to begin with, my experience so far with WoC has been that sooner or later everyone and their allies will hate you and you have 3-6+ stacks following you around, whether it's Kislev, the Empire, Ostland and whatnot or mixture of several factions.

1. March ASAP to Baersongling's camp and vassalise it. This allows you to gain some "safe" ground to replenish early on as you might be moving around the area quite a lot. Unlock first tech tree as well.
2a. Raid Volksgrad (or whatever that Kislev province next to Baersongling's camp was) and sack the settlement there. Keep in mind you might draw in plenty of stacks.
2b. Head to the remaining settlement the tribe has, recruit some marauders and prepare for bit of a rough battle.
3. Upgrade your camp to lvl2 ASAP once you have enough income in stock to stay still for few turns.
4. Get chaos warriors ASAP.
5. Go on a rampage and wipe Kislev out, then focus either either on one of x-lands or Kraka Drak dwarf faction. After that it's however you see fit.
6. Pull wet spaghetti and don't push it, aka unless you absolutely need to make max distance, leave some safety margin in your movement.
7. Only unlock tech trees when you accumulate enough income that you're not wasting your entire stockpile.

If you survive past 20 turns by near-nonstop fighting, you have gained enough income stock that you probably survive through rest of the game. If something went wrong, just restart the game or make some backup saves and consider alternate choice of action. As counterproductive as chaos warriors early on may sound, there is one major problem with marauder-heavy armies early on and that is, if you have 2-3+ full stacks following you around, you will lose. With chaos warriors, AI will almost never engage you unless they have extreme superiority of numbers or without an ambush. Now if you see three stacks disappear, just walk into the ambush. Chaos warriors + ambush means you have less distance to run to fight, which in turn means you will chew them for breakfast, which in turn means you can be very aggressive and dictate your pace of engagement even on the map without relying too much on agents to even the odds, and instead you can keep them in your stack as relatively huge force multipliers.

After all, if you have to replace ½ of your marauders every turn if you are sandwiched vs maybe need to merge two chaos warriors together after several lightning strikes fought on the same turn, the cost efficiency of marauders become notable zero sum game. Once you have enough income in stock and you plan out what you want to use, having some marauders as expendable meatshields (warhounds are decent early on for this as well + allowing you to chase tons of routed units effectively) is not a bad idea. But early on, it is more than likely you have ½ of Imperial factions tailing you at once unless there's massive "world war" going on that distracts the AI, during which marauders cost-efficiency means you are fighting very losing battle in terms of numbers. You lack serious force multiplier to win multiple battles in the same turn without severe losses or if you end up being attacked with 3x stacks in the same turn. Warhounds and marauder horsemen can supplement lack of regular marauders, as you can easily flank horsemen behind a melee ♥♥♥♥♥♥♥♥♥♥♥, throw some javelins or drive off ranged units and make sure they won't be shooting anything. Also don't forget your heroes + lords are bulldozers on their own as well.

Main downside is, if something goes wrong early on it tends to result in a restart, but then again even with less aggressive in terms of income the same "joke" is often guaranteed (based on my experience, so anecdotal and all) to happen only marauders are even less capable of dealing with it.

Edit: As far as lord skill trees go, besides obligatory lightning strike and whatnot, only thing you will really need is hearts of iron. While buffing your troops further works, it is rather redundant as you already have some of the best melee units in the game and the choice between turning your lord into even better bulldozer to supplement your other bulldozers vs having slightly improved bulldozers, the latter has less leg to stand with as you can basically forget you have a lord fighting unless it's surrounded by multiple elites or anti-x units.

Addendum: Having chaos warriors doesn't mean you'll fill your stack with them right away, as that's unsustainable. What it means you try to aim for 5-6CWs at most early on in your stack instead of 10+ marauders, and balance it out so you are making as minimal income loss as possible depending what units you want to keep in your stack and what to disband.

Similar to the last post, try this for Archaon.

Turn 1: move towards Baersonling w/ 75% of movement, go into encamp while tresspassing, upgrade horde building and get first research "The Path to Ruination"
Turn 2: Attack Baersonling, vassalize, research "Skulls for Skull Throne", remove 2 marauders, move as far as possible to Volksgrad without trespassing
Turn 3: Rumors are false or true, your choice> AttackVolksgrad (even if Kislev moves an army over here this early you can safely win auto resolve and only lose 2 hounds), raze for nurgle.
Turn 4: Yes or no for beastmen, your choice> move to raid Praag, makes more money than Sjoktraken
Turn 5: Follow carfully! March> go towards Sjoktraken just a into a bit of the mountains (between the two batches of trees in the pass)> recruit lord of your preference, army buffs preferred> Run away from your new horde to prevent attrition, if possible, move towards Baersonling for replenishment> Set lord new lord to raze and recruit an exalted at new lord
Turn 6: Move new lord towards mountains with Baersonling and encamp, this is for scouting andchaos corrupting Praag, embed exalted in new lord army, swap Archaon to raiding and stay close to border of vassalized norsca while raiding Frozen Landing, research Rituals of Corruption

Traits: In order of selection
Archaon:
- Grand marshall of chaos
- Route marcher
- Tribes of Chaos x3
- Despoilers x1
- Unholy resilience
- Despoilers x2
- Lightning strike or gathering of might, preference but get one after the other

First Lord:
- Route marcher
- Tribes of chaos x3
- Serve or die x1
- Unholy resilience
- Gathering of might x3
- Serve or die x2
- Lighting strike

With this build the new lord will be rank 6 upon hiring and allow for fast growth through campaign skill tree "Tribes of Chaos" for 7 growth a turn. The exalted in his army also helps him gain experience over time and allows for assaulting oncoming armies before they reach Baersonling for a better chance your tribe lives. Your income will be on the up and up, and from here it's really how you play. My second lord I intend to use as an settlement when I push into Kislev's territory, hence "Serve or die" as a priority, by then I aim to have enough growth on Archaon to get the dragon ogre building and hire Kholek as a second army lord. In the meantim while waiting for growth I'm gonna march through the norsca and dwarf provinces and vassalize what I can.

This six turn setup is the best I've been able to manage.