For what it's worth, this is the breakdown of teams to be faced:
13 Games: ATL, MIA, NYM, PHI
7 Games: COL, PIT
6 Games: ARI, BAL, CHC, CIN, LAD, MIL, SDP, SFG, STL
3 Games: BOS, CHW, CLE, DET, HOU, KCR, LAA, MIN, NYY, OAK, SEA, TEX, TOR, TBR
The Nats were surprisingly 25-27 against the NL East last season, mainly due to owning the Marlins (11-2) and beating up on the Braves (8-5). By contrast, they sucked against the NL West (10-21), especially the Padres (0-6) and D'backs (1-5). They were 15-18 against the NL Central. The series against the AL (except Baltimore) were a mix of 1-2s and 2-1s, except for going 0-3 against the Royals.
In terms of how this and the off-season moves change a projection for this season, I find myself unsure. For example, the Mets are certainly improved, especially with Soto, but we were 2-11 against them last season, so it's not like their improvement changes much. Maybe we lose another game to the improved Dodgers, but pick up a win or two against a weaker Padres club.
So, I'll just make a random prediction of incremental improvement and say 74-88.