[neferhet]

My humble suggestion

Chaos Lord w/ Sigil & Claw, meltabombs, Mark of Nurgle
=125
You dont' want him stuck against some AV12 stuff...also complements the unit he joins

10 Chaos Marines
-2 meltaguns
-Rhino
=195

in my experience, meltaguns works better, just becuase you will be soon riding in range to kill stuff. Also, they don't fry your models and can threaten vehicles more reliably (explosions on 5+, sweet...)

9 Chaos Marines
-Meltagun
-combimelta & meltabombs
-Rhino w/ combimelta
=197

you don't want them in melee. the lord is a melee deterrent for the enemy, more than a beatstick for you. also, now you have a potential 3 melta shots. Toughness 5 helps against instadeath and small arms fire. Maybe Tzeentch is better though.

2 Obliterators
-Mark of Nurgle
=152
--------
Helbrute
Heavy Flamer
=115

Helbrute
-Power Scourge
=110

Helbrute
-Reaper Autocannon
= 105

the three deepstriking helbrutes are better if you scatter weapons around. otherwise the opponent have to kill just one brute to remove two weapons.

Total - 999.