As stelek as said, good combination of the fire and meat shield, but you might want to concider a unit of bloodletters, that army tends to lack a serious punch in
CC, also, a daemon prince would make a nice tank hunter in the army, wings are high points for him, but its worth it to take out any major threats to your army, as something like a vindi or russ could make a mess of units at a time.
i tend to find nurglings a waste of time, most people will ignore them as they are rarely a threat, and i think 6 flamers is slight overkill in a 2k points game.
but thats just my suggestions, good luck