Hiring a nanny who is working out of her home

I'm going to potentially hire a nanny who will take care of my son.  All work will be in the nanny's home but I will likely give instructions on how to perform the care and provide supplies like diapers and food.  Would this nanny be a household employee and would I need to make her a W-2 employee?  Or, since all the work is at the nanny's home can I use that fact alone to say this is not a household employee (and just pay her and not worry about W-2s or 1099s)?  

 

Furthermore, is there anything I need to fill out in advance to verify or document this isn't a household employee?  Perhaps a contract with the nanny that indicates the work will be at her residence?  Or is there a specific IRS form I can use to confirm this individual is not a household employee?