When a childcare provider will not give you a SSN or Tax ID

If they still refuse to provide an EIN or SSN, send your provider a W-10 (Request for Taxpayer Information and Identification Number).  You can get a copy of the W-10 by clicking here: W-10 Form & Instructions  Complete as much of the form as you can and send it via certified mail (after making copies for yourself).

If the provider does not respond within 10 business days, you can still file your return.  However, you won't be able to e-file.  Print and mail in your return, along with an explanation and a copy of the W-10 you sent your provider.

https://www.irs.gov/individuals/international-taxpayers/taxpayer-identification-numbers-tin

"Nanny"?

This isn't your question, but I thought I would mention this just to warn you about potential problems and/or to help you with future situations.  A "nanny" is typically somebody that works in your home watching your child, and that usually means they are a "Household Employee".  That means that in most cases YOU should be paying Social Security, Medicare, Federal Unemployment, and possibly State Unemployment, Worker's Compensation or other state requirements for that "nanny" (but there are exceptions).  Plus you would have been legally obligated to get her information (including her Social Security Number) BEFORE she started working for you (to verify she was eligible to be hired).

Again, that isn't what you asked about.   But you may want to be aware that if you were required to do such things and did not do them, it is possible that the nanny will notify the IRS (and/or the state Department of Labor) about it and the IRS (and/or the state Department of Labor) would eventually contact you.

@xmasbaby0 's answer applies to claiming the child care credit only.

@AmeliesUncle 's answer is actually more important, because missing the credit means missing the credit, but you can be penalized if you don't issue a W-2 when it is required.  If you pay a nanny to work in your home, and you pay them more than $2200 per year, you are required to issue a W-2 and pay household employee tax.  You are supposed to get their social security number before they start working for you.  

If you can't get the SSN by December 31, there may be a way to issue one without the SSN, but that's complicated and hopefully you will work it out before then. 

@odinglett It is good that a couple of sharp users here are pointing out that you may have had a household employee for whom you should have been withholding Social Security and Medicare, and for whom you may need to issue a W-2.   We do not know if the childcare provider worked in your home or somewhere else---we cannot be sure if you are using the word "nanny" more casually to refer to someone who babysat in their own home or in your home.

Going forward, if you need to employ a childcare provider so that you can work, you need to have a clear understanding from the very beginning with that childcare provider.   You need to make clear to them that you will be claiming the childcare credit and that they will need to report that income on their own tax return.   They need to provide a Social Security number to you or if they (understandably) do not want to give out their SSN, they can get a Tax ID from the IRS to use instead if they will be working as an independent contractor in some location other than your home.   What you should never do is take a childcare provider by surprise at tax time and announce suddenly that you are entering the childcare credit on your tax return and spring it on them that they will owe tax on their income.   The IRS matches the amount you enter on your tax return for the credit with the income reported on the tax return filed by the childcare provider.

https://www.irs.gov/individuals/individual-taxpayer-identification-number

https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/considered-household-employee/L...