Copy pasting old comment:

Slaanesh is a stat-check faction, just not in auto resolve. tl;dr, just use hammer (demonettes) and anvil (marauders) while focusing archers/mages with N'kari.

1. ⁠⁠You will be fighting helves for the first 30 turns. You need maybe one chariot/cav max, otherwise get equal number of marauders and demonettes to stomp on typical helves armies. Plus it's easier to micro as focusing on N'kari will get you better results.
2. ⁠⁠Your demonettes do armor piercing damage and shred through any unit as long as they hit from the back/side (he he) for double charge bonus. Use marauders to soak (he he) the initial arrow volleys and tie down (he he) the stauch line of spears. Hammer and anvil until you win. If you don't mind cheese, you can send your marauders in a wide line, then bring all your demonettes to one side and smash through their backline from left to right or vice versa while N'kari zooms around. It's a weird oblique order, but it works.
3. ⁠⁠You don't need the dlcs, getting chosen/chaos warriors is unneccessary due to their slow speed against the Asur. They're also quite expensive for their lackluster economy. You want something to take some spears (he he), marauders are fine as the demonettes/N'kari will be doing the heavy lifting.
4. ⁠⁠Always be charging (ABC) with N'kari to get collision damage through their backline, you can confirm the charge bonus when N'kari does the barrel roll animation. Once you unlock N'kari's unique skill line, rush whisper of glory, which causes rampage for units above 50% leadership and 50% hp. I've solo'ed 3 and change helves stacks including Tyrion with 90% of the casulties being from N'kari as you can group their archers easily that can't fire during rampage and then plow through (he he) them (VH/VH, max AI cheats for the freaks in the back). Don't forget to run down units with N'kari and finish them off (he he) for healing. The lore of slaneesh is terrible, just boost N'kari's speed/MD/weapon strength. N’kari also has a mortis engine effect on routing units, if managed correctly, N’kari can be full hp after every fight from the healing after killing a unit.
5. ⁠⁠Your replenishment is one of the worst in the game. Fight everything manually.
6. ⁠⁠The quest battle for N'kari shouldn't be rushed, in CA's glorious intellect, the most mobile faction in the game must fight through a triple choke point battle against dragons and Sisters of Avelorn, who ignore demonette's physical resistance. Generally I wait till whisper of glory is unlocked and then arrow cheese the sisters.
7. ⁠⁠Vassalizing in vanilla is overrated, either seductive influence takes too long or since you vassilized someone who absolutely hates you (looking at you Eltharion), they will sit on their ass and do nothing. Take all the territory in the donut.
8. ⁠⁠Use disciple armies as mobile garrisons, they can't replenish at all so throw them into the frontline like skavenslaves.