Tips on chaotic Sims 3 Gameplay?

You could take a look at the ISBI challenge, not to really play it but for the basics.

You control only one sim in the household (who must be insane) and let the others run wild.

Insane is a trait I would recommend anyway, daredevil, diva, evil, flirty, hot headed, slob or grumpy (a lot of the "bad" traits have great interactions).

As for EPs, probably ones which give a bunch of social interactions and stuff to do, like generations or seasons. Supernatural, if you like it.

Also, totally recommend nraas mods, especially if you want to spice it up a bit.

(FakeGamerGirl is awesome)

ISBI is really awesome for chaotic gameplay as @Waterdragon has stated; also if you have a cracked sense of humour to provide a narrative that absolutely makes people roll out of their chair laughing. ~evil smirk~

ISBI (if you're not familiar with it) is a game where you set your sims on high-willpower (and let them do whatever the heck they want to) - set all your sims except for one (or if you really wants ****s and giggles, you can set ALL of them to insane). You only direct one (if only for the case of insane sims tending to not give two hoots about their continued existence)...that's only for the sake of being able to continue the game, one of them has to cook or they'll all starve to death. And secondly, you set everyone else in the game (except for one that you control) to NPC. Then let the chaos ensue.

My ISBIs tend to devolve into complete utter insanity. It also helps that the Watcher has a few bricks short of a full wall. ?

Meanwhile, Jen was having a vociferous argument with the toilet.
https://i.imgur.com/hIQbppS.jpg
Poor toilet, all it does is sit around having to take carp from people. C'mon Jen, leave the poor toilet alone...if you insult it too much, it's going to have an emotional breakdown; might end up with a lump of something stuck in it's throat...probably toilet paper.
https://i.imgur.com/Y5fKUET.jpg
Of course there was only one toilet and that meant that no-one could use it with Jen haranguing the commode...and a lineup ensued.
Meg: "For crying out loud, Jen, it's not going to answer you, so leave enough alone, will ya?" https://i.imgur.com/xRcQ6tK.jpg

I haven't done an ISBI in a long while. It takes having a cracked sense of humor and being able to see the off-beat side of things.

For those that don't know, ISBI means "I'm surrounded by idiots." The other roommates in your house are controlled by the computer, hence they're the idiots. :D