What happens after I list my nanny's personal information with the FSA to claim dependent care reimbursement?
Is this information shared with the IRS and will she be responsible for taxes?
If you have a nanny, not a day care center, a nanny you hire, you are responsible for the Nanny Tax, i.e. taxes regarding a household worker. And yes, she's responsible for income tax.
This is not the board to talk about "chances of getting caught," but I'd respectfully suggest you not take advantage of a particular benefit if the rest of the process isn't above board. Claiming the deduction, the FSA, but not handling the rest of the obligation, tax-wise, isn't something to risk.
Yes, the information can be shared, very easily.