As a live in nanny of a few years who has recently made the transition to live out the advice I would give you would be:
- House rules for your children: no going into nanny's room without her permission, and if her door is closed then do not disturb. Over the weekend when your nanny is off duty then remind the children to let nanny do her own thing. We will often be polite and play games with the kids if they catch us unaware/when we get in from shopping etc. Call the children away from your nanny unless she insists.
- Decide in advance if you have a curfew (I don't personally think this is necessary as nannies are adults and entitled to a life). I once started a job only to realise that I had a curfew on work nights that wasn't mentioned at interview. Clarify these things beforehand.
- Guests. Perhaps chat with your nanny about who can and cannot stay. Whether you allow overnight visitors etc.
- Cleaner. If you have a cleaner will they clean the nanny's bedroom and bathroom or will she do that herself? I did mine myself and preferred it that way.
- Food. My boss kept an ongoing list in the kitchen. I added things we needed I saw we were running low and anything I liked in addition. I would sometimes forget to add the things I liked to the list but my boss would get them anyway - that was really nice.
That's all I can think of right now, but hope it helps