Aside from general questions, consider asking questions related to toddler's.
For example: How would she deal with certain scenarios? What about injuries? Crying? Temper tantrums? Ect?
How does she discipline children? Time-outs? Taking toys or tv away?
Does she have any certifications? CPR, Nursing, first-aid?
Does she have her own vehicle?
Is she open to play dates?
There's a whole slew of potential questions to ask! It really just depends on what you're most concerned with.
For more questions read this post: Nanny Interview Questions For All Ages
(these questions can be used for both nannies and/or babysitters)