Hi there,
While possible, this will be a hard transfer to make in case of a delayed plane or busy day at the airport.
The last train connection departing for Kyoto and Osaka from Narita Airport that is covered by the JR Pass departs at 18:48.
The route looks as follows:
Narita Airport - Shinagawa (19:58)
18:48. LTD. EXP NARITA EXPRESS 46
20:10 Shinagawa -> Shin-Osaka (23:16)
SHINKANSEN HIKARI 533
You'd have 12 minutes at Shinagawa station to make the transfer there, which is enough.
I can't decide for you but it may be a safer option to travel into Tokyo and travel to Osaka the following morning. At the same time, Narita Airport can be finished in about 30-40 minutes, it all depends on what the queues are like. Though you'll also have to exchange the JR Pass and reserve train tickets.
Kind regards,
Daniel