The Nationals don't seem like players for Betts to me, since they have a full outfield with Soto, Robles and Eaton if they exercise his $9.5mill option, which they should.
Of course, they could exercise his option and include him in a trade for Betts. But their farm system is top heavy and bottom bare. It's hard to see them putting together a deal unless they decide to trade Carter Kieboom, which is VERY unlikely. Or if the Sox are willing to take 19yo Luis Garcia, which, while a good acquisition, does nothing for the 2020 or 2021 club...