After the last express trains there are a few slower trains - The old Skyliner at 10:29pm is a 60 minute ride to Nippori. From there, you can take the Yamanote line. I would recommend the bus rather than the slow train at 10:39pm -- since your priority is probably time and convenience rather than finding the cheapest route -- Last bus for Tokyo Station leaves at 11:00pm. At that time, the bus journey will be quick.

I think there's very little chance that you'll miss that last bus ... but let's just suppose you do ...

If you miss the last bus, your choices are a cab or a rental car or staying overnight at Narita. Car rental can be cheaper than cab - but some hassle to return. [Not sure where the closest 24 hour rental station is to Tokyo station - I've used one near Iidabashi for this kind of trip]. I would only suggest it if you're already familiar with Japanese sat-nav and feel confident about using it to drive into town. Cabs have published fixed rates for trips into the city, but I think those rates are probably bumped up for midnight trips.