[Khorothis]

Just so you know, 'nids can be turned into Chaos Nids with a clever paint scheme and minimal conversion (just put some random tentacles from a Chaos Spawn sprue somewhere every now and then). They're incomparably more competitive and fun than Daemons, since you actually have to use your brain A LOT to find out whats good in your Codex and what synergies work the best. Another good thing about them is that if you want to go for a shooty list on a whim, your Codex can come up with nice units and combos. Oh and they can mimic the Daemons' tactics with Mawlocs to some extent. Its also much better written (no silly +1A for a Khornate DP ).

 

[Khorothis]

This is bizarre I too am toying with the nids after discounting the BA's (purely due to colour scheme and well the need to avoid astartes)
So I would be interested in also finding out what are the more effective units for the nids!?
(sorry ROT for latching upon your thread)

There are some very nice and educational articles over at the Tactics and Tactica Articles sections, its worth reading all the ones for the 5th ed Codex because it will give you several perspectives and enough information to digest for a few days at the very least.