As you want to know about the Nanny and Babysitter so here I am telling you the deference

Nanny and Babysitter-

Hired for childcare and perhaps some additional duties on a scheduled full-time or part-time basis and may live with the family.

Generally an employee of the family, with the employer responsible for their half of the Social Security taxes and for income tax withholding.

May be paid a salary or hourly wage and may also receive vacation and/or holiday pay and perhaps other benefits.

Babysitter-

Provides childcare "as-needed" often for multiple families.

Considered a contract worker. The babysitter is responsible for all taxes.

Paid only for hours worked.

Part-Time Nanny-

Some families need a mix of babysitter and nanny.

They need someone to care for their kids a few hours a week (maybe only Monday through Wednesday or only after school).
But they want a caregiver who will be more involved that a typical babysitter.
A part-time nanny is as a rule the answer.
This option can provide the best of both worlds for families trying to manage responsibilities.