I think this is excellent advice. We do this exercise with both of our doodles for every meal. I think it is puppy biting and something that he will outgrow with time (Dexter had me in tears w/his puppy biting until around 4.5 months)...just keep saying "no" and give him an appropriate chew toy...it just takes some time. Another idea, you could try removing Oliver from the play area (either to his crate or another room) so that he learns the fun stops when he nips.