Suppressing a behaviour by force - such as when vets and vet nurses recommend holding a puppy's nose and telling him 'No bite' is likely quite painful.
Although a puppy may have temporarily stopped biting to avoid being hurt by his owner in the future, he will have no idea why he is being treated so roughly. Simultaneously uttering a guttural command or threat (i.e."No biting" = If you bite again I'll hurt you again, and this time for longer ) in English - or Swahili - mistakenly assumes a puppy is a mind reader or can miraculously understand a particular human language.
There is no guarantee that the biting won’t happen later in life if, for instance, somebody accidentally steps on his tail. What many people don't realise is that biting is an invitation to play and when littermates continuously do so they mouth and bite each other all the time. If one puppy bites another too hard the game ends as the bitten puppy yelps and moves away; so if the biter wants to play again he needs to solve the problem himself by modifying the force of the bite and not to do it so hard the next time. This is a continuous and VERY necessary learning process throughout puppyhood, adolescence and adulthood.