The basics are these.
There's two types of strategies you can run...two schools of thought. And maybe you would prefer one over the other, but to be efficient I would recommend you use both with accordance to match-ups and opponent.
You can play a safe zoning NM with a lot of backwards movement.
You can play an aggressive in your face NM with a reliance on throws and sidestep.
The first option is especially useful if whiff punishing is you go to strat. It's relatively safe and utilizes NM's long range and back dash without taking many risks. Your aim is to bait out attacks that aren't likely to land on you, in attempt to open up your opponent for punishment. This strat frustrates opponents who are especially aggressive, since they have to chase your NM down to apply any pressure. The weakness of this strat is that it relies heavily on your opponent making mistakes. Doesn't put any considerable pressure on your opponent, because you can't throw while back dashing, and your probably putting your back towards the edge or wall.
The second option is very useful if you want to apply pressure. It might not be as safe, but you will find many match-ups or opponents that you have to apply this strat to win. Up close NM is open to utilize his throw/mid game. That's his strongest mixup the reason his front throws are nerfed. A forward movement NM is more likely to land wall combos and ring outs. Sidestepping is your main tool for whiff punishment, but you can still setup backdash for whiff punishment.
