It usually depends on the time of the league and your ability to invest time.
Item/currency flipping is the most chaos/hour, but it isn't for everyone. Early on in the league if you get your masters to level 8 very fast, you can also make a huge amount from selling your services. I only flipped currency for about a week and was getting a little over 400-500 chaos/hour depending on times. It could have been more; I was very new to it all and wasn't in every market.
Boss killing is also much more profitable early on, both in terms of the items and boss killing payments, but drops dramatically as the league goes on. Chaos/hour will depend on what you kill, and early on very dependent on your map drops, but it's quite high.
Uber lab can be extremely lucrative if you're willing to put in the time to learn how to do it fast (under 5 minutes at most) and can stand to do it dozens and of times on a good layout day. Chaos/hour various quite a bit depending on what enchanting strategy you go for (helm enchants on popular helms hoping for a big payout, or boot enchants on common boots for a more consistent stream), your speed, and the layout, but from my experience I'd average it out to maybe 150-250c/hour.
"Good" mapping strategies, actually playing the game, can vary quite a bit depending on how you do it, but from the data, people post here it seems to be somewhere in the ballpark of 100-300 chaos/hour.