This is the build that I have been using so far. I just started nightmare last night and played a little through it without any major issues.
What I usually do is wait for my pets to go out and attack some enemies which doesn't take long. I'll go in, use soul harvest, then drop and acid cloud followed by firebomb spam. Depending on the situation I'll use more acid cloud or locust swarm, and everything is dead usually within a few seconds.
To players that are further than I am.. do you think this build will last long or will I find out shortly that my pets will just die instantly? Also.. I'm level 33 (I think, lol)