Get her a credit card, or open a bank account with her on it.
I get why people suggest low limits, but I have been given a card with a $30k limit more than once. $1k was never enough for long. I was taking cars for tires/repairs and put gymnastics class and speech therapy on the card.
More for other readers: do not ask your nanny to loan you money for groceries, then get reimbursed later. I honestly won’t even work for people like this anymore.