'A nod in the right direction' means some advice or help to s.o. : 'I gave him a nod in the right direction'

A nod is a movement of the head to express a nonverbal message. For example, if I want to motion for someone to go ahead of me in a queue, I could nod my head in the direction of the queue. Or if someone asks me a question, "Have you seen my dog?" I could nod my head in the direction that I saw the dog run.