I'm confused, to legally hire a nanny you need to start a legal entity and hire the nanny as a contractor/employee? It seems to me that this would be the nanny'

I'm confused, to legally hire a nanny you need to start a legal entity and hire the nanny as a contractor/employee? It seems to me that this would be the nanny's responsibility to start a business and charge the customer (you) money for their service. I'm sure you're much more familiar than me, can you help me correct my intuition?