Tips on having a nanny please

This will be my first time hiring a nanny and I have 2 trial runs set up with potential nannies to see how they are with my son.

Does anybody have any tips for me? Maybe things I should be observant of?

Personally, I would watch for how the nanny reacts when your son is being a little bit difficult. Not all children are going to cooperate all the time and it would be nice to know that the nanny can handle it the right way

I like to see how the nanny speaks to the kids and how she gets them to do certain tasks like eating