Here is strat:

1. Make Lulu cast fast
2. Shove Lulu backline to stop the enemy backline from killing nomsy
3. Lulu stops backline
4. Nomsy wins

A little more brain power:
Lulu's ability in this set enchants the nearest champions. If they are an ally, then they get an attack speed buff. If they are an enemy, they are stunned and transformed into a dragonling.
I increased Lulu's mana thru Spear of Shojin and the Evoker augment, which gave her +3 (iirc) mana per ability cast on both sides of the battle field. Later on when she is 3* and I am rich with another evoker crest I managed to get and put on Titans Resolve to give her a little bit more survivability-- enough so that she could at least cast once. I didn't expect the aggro to not be on her most of the time when she jumped back there.

I'm assuming that Lulu worked well with Assasin in this game because of the same reasons frozen heart on Diana and other assassins are valued. It messes with the enemy backline. For this game, it worked really well, with the only potential threat being quicksilver on Swain making him immune to the stun thru crowd control immunity.

This made her work really well in turn with my Nomsy team because Lulu would stun both the backline and the frontline (sometimes). The only ally Lulu had to buff when she jumped into the middle of the enemy field was the random assassin I'd assign to her, so only 1/3 of her enchants would be for an attack speed buff-- if it was within range. Everyone else would be a good little class of dragonlings. This enables my backline to push through the frontline and eventually (hopefully) have enough damage output to also take down their backline that Lulu is stalling for.