Hey there...
I play Nurgle themed
CSM.
Zombies are okay... their biggest problem,
imo, is that they're slooooow. Either keep them in 10 man squads for objective camping / meat shield. Or go large unit (x30 zombies) to deliver a baddy, like Typhus.
Tips for painting the Hellturkey. Don't assemble the model first. Paint the pieces individually... you'll thank me.
Consider the Zombies from
Mantic.
Consider adding Huron to your army in this list... his ability to re-deploy some units is almost imperative to minimize the distance between your zombie hoard to the nearest enemy unit.
In a slow list like this, you really need something fast to keep your opponent occupy. Think about getting 5x Nurgle Spawns... they're a great distractors.