Baby getting used to confinement nanny

My confinement nanny has been with us for 2 weeks, and baby is showing a preference for her when it comes to calming him down to sleep. He would continue crying when me or my husband try to carry him to sooth him to sleep,but calm down with the nanny and sleep. However, as the nanny will be gone in 2 weeks,I am concerned that baby becomes over reliant on her and would be very hard to calm down after that. Would like to ask if anyone has similar experiences, and what you did to overcome it.