I'm a nanny, would i be considered self employed?

That depends.  If you work in someone else's home according to their schedule and their work rules, you are usually considered their household employee.  They are required to pay wages, to withhold social security and medicare tax, and issue a W-2 at the end of the year.  If you work out of your own home, or you work for several families in their homes, but you are able to set your own work conditions (like time off for appointments and vacations) then you are probably self-employed.

It's all about independence and control, who has more control over how, when and where you preform your work.  This PDF may help.

https://www.irs.gov/pub/irs-pdf/p1779.pdf

Unless your employer paid you through a business, deducted taxes, and sent you a w2; yes you would be considered self employed. You'll have to fill out a schedule C to report your income. The good news is you'll be able to deduct expenses associated with your position. Such as mileage, any uniforms needed, etc. If you have a little knowledge of taxes, TurboTax home and business will walk you through everything. Otherwise, it might be a good idea to enlist professional help. Good luck!

If you’re a nanny or other worker who cares for others' children in their home, the IRS likely considers you a household employee, not an independent contractor.

For more information, please  read this TurboTax Help article: Guide to the Nanny Tax for Babysitters and Employers