Hello and welcome to the forum.

Puppy biting needs nipping in the bud asap as im sure you realise. I think the saying no and treating is a good thing to try, but you dont want it to come across to the dog as if he is been rewarded for the biting in the first place.

What worked for me was to say no and then just stop what i was doing with him and ignor him. Ideally the kids also need to treat it in the same way or he might think he can still get away with it. It may also take a bit of perseverence.

Have you got a check or half check collar? These can be usefull when training in general as the dog will get used to the noise of the chain as a reinforcement. Personally I prefer the half check.

Another thing to try which could be usefull is a shaker. Just put a few stones in a small plastic pop bottle and give it a shake when you say no, this usually makes them jump a bit and listen.

Good look and keep us updated as to how its going.