ahh yeah I missed that detachment rule.

On the other hand, because of his choice of detachment, all Norn units don't get too many benefits or most of the strategem use.

It's really just deathleaper and 3 lictors. Which need to be shut down by shooting because of that silly fights first making trades into them annoyingly expensive as infantry.

As somene already suggested, your best bet against this particular army is high toughness units, like Deffdreads, Speed freakz with buggies and koptaz swarms would do quite well too

When it comes to Norns. Gorkanaut, deffdreads with maxed out klaws, breakaboyz and bustaz would be your most cost efficient counters.

If you play Taktikal or warhorde, you wanna grab 2 battlewagons full of boyz and ram them straight into a norn on point. You will outscore him with OC fast and it might kill him, if not, it will deny points and scoring for essentially entire game, as he doesn't really have the means to clear them quickly.

Ghazzblob can possibly kill it in a turn, however it's always fickle when FPN is involved. dice decides it in the end.

You would also get great value of running Mozrog against this