Nanny needed for one half hour per day

So we're thinking about what to do for our babysitter-enabled evening this weekend, and we realize that what we really want most is to have someone get our kids ready for bed. The bedtime routine of prodding, cajoling, and (usually) threatening the kids into their pajamas is a brutal gauntlet at the end of a long and tiring day. Can we hire a nanny to just get the kids ready for bed, then we'll come in and sing or read to them? That would be awesome.