Kassandra Fields-Ralph is charged with lewdness, child endangerment and theft.
South Brunswick Police Sgt. James Ryan told The Homes News Tribune of East Brunswick the investigation began after the child's parents told police they suspected the 38-year-old was stealing from them.
Ryan says the video showed Fields-Ralph urinating in the sink three times and taking a sweater.
The Perth Amboy resident is a licensed practical nurse who was hired by the couple because their child has special needs and requires constant supervision.
It is not clear whether Fields-Ralph has hired an attorney.