A set routine where things become increasingly calm - make the house dark, cool and quiet with soft music
Figure out the root cause of the behavior -
if baby is cling-y it might be not that he is fighting sleep but rather fighting being put down alone - try wearing him in a sling and letting him fall asleep while wearing him. Babies need lots of skin to skin contact - if you wear him in a sling while in a tank top this is going to help a lot. Mom should do this as well once she is home each evening - babies WILL get their snuggle time one way or another - you must fill them up on skin to skin snuggle time before expecting him to sleep.
If there is a routine where you feed him and then try for a nap - be sure that what he is eating isn't upsetting his tummy - what seems like fighting sleep can actually be upset tummy (squirming, twisting, crying, twisting in your arms - all signs of upset belly) - so what will help is having a BM before the nap - tummy time, a warm bath, warm oil massage can all help with making sure he isn't trying to digest while you are wanting him to go down.
Cry it out sleep training is not reccomended by most who follow attachment parenting. If I were paying a nanny I would expect my child to not be in bed crying himself to sleep. You know?
