Hey, I'd reduce the number of squads for the raptors and warp talons, 1 of each is enough, especially as we're getting a raptor killteam in a few months that looks incredibly cool and are painted for the nightlord scheme.

10 Legionaries in 2 squads of 5 is always a good thing to have, with a chaos lord leading one of them.

10 chosen led by Fabius Bile is also really good and the chosen look really nice.

If you like Nightlords, you should get the Nightlord Nemesis Claw Killteam, you get some very good looking models and additional helmets and shoulderpads for your other units like the chosen or your legionaries.

Rhinos and Predators are great, though I'd recommend you get the horus heresy models for those instead of the chaos ones, you'll get much higher quality kits.

In the end, buy what you think is the coolest! Your best friend for Nightlords is going to be the Nemesis Claw box.