Yes in a way. The main thing in 3.0 is being able to carry out your battle tactics and grand strategy. There are a few that are easy to accomplish to start the game but the tactics that win you games are being able to kill the general, battleline, and monster, along with the added bonus if you do some of these items with a monster.
Nagash fills out that roll very well, being able to delete units and get the added bonus for being a monster. He's not unkillable though so you have to be careful when running him.
The main strategy to protect him and increase his maneuverability is using Protection of Nagash to teleport him when he takes damage and out of combat.
Playing the objectives is required to stay in the fight but in most case won't win you games. Playing to the strategy and tactics is what wins games and Nagash does that better than everything else in our army until our book gets fixed.