My Mini Schnauzer Puppy Loves To Bite - how do i Stop Him?

by Linh
(Sacramento, CA)

I just brought my mini schnauzer home last week (at 8 weeks). He is a great puppy with a lot of personality so far.
However, I have noticed that he loves to bite or nip at you. (Well it's not so much biting as it is just closing is mouth around whatever part is in front of him and then gnawing at it) It doesn't hurt of course because he's so tiny and doesn't really put a lot of force behind it.
However, I don't want him to get used to doing this, especially since I have little nieces (6, 3, and 6 months old) who come over a lot. Is this just a phase he's going through? And how can I train him to stop?
I tell him no when he tries to nip and my hand and my husband uses the Cesar Milan technique by prodding him with 3 fingers and saying "CHH!" but I don't want to scare him because I feel like we might be too rough.
Any suggestions?
Thank you!