First of all, if Nixon finishes his term, I feel like there might be a kind of peace deal in Vietnam or at least some recognition of South Vietnam being left alone or having it be quite small compared to the north. Nixon is going to want "Peace with Honor" while also looking to seem like the war was not totally a lost cause, so I'm guessing he'll try to make sure there's some sort of South Vietnamese state, even if its just a smaller area around Saigon. Granted I don't know how the US would get the North Vietnamese to accept this, but I just feel this would be the way for Nixon to do this, and with his success in regards to regularizing relations with China, I could see how he feels he could get the North Vietnamese to work something out.
As for other issues in his term, Nixon would probably still try to fix inflation by having tax cuts, but he'd also still be seen as spending too much by passing things like the Education for All Handicapped Children Act, and many in his own party might argue that this is a state issue and that since the states deal more directly with education, this will be seen as a way for the feds to get more control of education, and many will see Nixon as simply trying to expand government, against many in his party, and as well as conservative Democrats. He'd also probably speak out against Roe Vs. Wade, but not necessarily against abortion, saying again that it’s a state's rights issue. While some pro lifers would not be happy, many conservatives would argue its better than the status quo after Roe, and you'd get many Republicans and even a good number of Democrats at this time to argue that Roe went too far and thus, you see Republicans try to make bills that restrict abortion access and also campaign for the court to take a case to reverse it. Nixon also voices opposition to school bussing, and tries to smooth it over by emphasizing the importance of neighborhood schools and emphasizing that school districts need to focus on better schools for all rather than diverse schools saying that "better education is going to help more than dropping children from all over kingdom come into one classroom hoping things will work out."
In regards to elections in 74, if Nixon is in, I still think that the Democrats still get a lot of seats but not as many as OTL. I'd say that 270 is probably where they land, meaning they do have a big majority in the house. In the Senate the Democrats lose seats and notably regarding OTL, Patrick Leahy is defeated in Vermont, and Richard Lugar becomes Senator in Indiana, though the Democrats still hold 55 seats, putting them in the majority.
In the end, with no Watergate, Nixon is seen as a decently competent President, and is particularly lauded for his visit to China and for brokering peace in Vietnam, even if many in his own party don't see it as much of a victory. He also is lauded for creating things like the EPA, but again many conservatives still feel that his presidency spent too much and in their opinion, kept liberal and moderate republicans on life support.
As such in 1976, the Republican primary to me looks like a less intense version of 1964, with Regan leading the Conservatives, Rockefeller leading the liberals, and Gerald Ford and George HW Bush trying as moderates to keep the party together. However it becomes evident that with such challengers, Reagan wins in a plurality in the early primary states, with Reagan winning Iowa and New Hampshire, and forcing and Rockefeller to drop out. Reagan does lose earlier New England primaries in Massachussetts and Vermont, as well as Illinois, but wins in Florida, comes a close second in Wisconsin and racks up victories in many southern and western states and eventually wins in Ohio. Reagan then wins the nomination and choses Bob Dole of Kansas as his running mate.
As for the Democrats, with no Watergate, the primaries are wide open. Jimmy Carter still runs, along with Mo Udall, George Wallace, and Scoop Jackson. Carter still picks up a victory in Iowa, but few seem concerned. With Carter unable to play the Washington outsider game, and George Wallace also running, Carter still picks up some delegates but in the end, Mo Udall comes out on top and is the nominee, Lloyd Bentsen nominated as Vice President, thus providing a link to the South while still having a more moderate ticket.
In the end, Udall wins a close race, and in particular, closely wins a number of midwestern states, while Reagan sweeps the South and in the west, only loses in Oregon, Washington and New Mexico. While some Republicans argue that this shows that Reagan and the conservative movement are not as palatable to those in middle America, Conservatives see it as a sign that they are winning and Reagan himself says he'd be ready to go again if necessary. In the Senate, a 50/50 tie also occurs, though the Vice President is the tie breaker. Meanwhile in the house the Democrats lose seats but still have 255, keeping their majority.
With Udall in the White House, the main focuses domestically are fixing stagflation, providing healthcare for all, and working for environmental protection. Udall does end up supporting a universal healthcare plan and it does make it through the house in 1977 it is stopped in the Senate as a few conservative Democrats voting against it, though an employer mandate to provide catastrophic insurance does pass. It is with the economy though that Udall struggles. While the economy grows and unemployment shrinks, inflation continues to rise and with the energy crisis of 1979, Udall seems clueless on the economy. However, he does get praise for his environmental record and does get credit among some for promoting green energy at its early stages.
In foreign policy, the big thing is going to be that there will beno Camp David Accords and as a result there might be future troubles between Egypt and Israel, as while Menachim Begin does support leaving the Sinai, many Israelis do not, and thus Egypt and the Arab world continues to not recognize Israel, though Sadat does still try to work on some sort of peace deal, though relations remain tense. There also is the Iran hostage crisis which mostly plays out like in OTL and the Panama Canal Treaty, where Udall makes a deal to let Panama have control by the end of 1999 as in OTL.
By this point, Udall, much like Carter is defeated by Reagan, and in the end things are not too different. Udall, like Carter is seen as a failure, though among liberals he is still more liked than Carter, though he doesn't have the humanitarian record like Carter in OTL. He loses the 1980 election by a larger margin than Carter, though he does get 110 electoral votes, with New York being the largest state he wins along with Minnesota and Wisconsin. As for Carter, he tries to run for senate in Georgia in 1980 but loses, in a year where the Democrats fall to only 33 seats and lose the house.
So basically there are a few differences, but in the end not much. Basically Jimmy Carter is unknown outside of Georgia, Nixon is has a bit of a better reputation, and there might be a bit of delay in peace between Israel and Egpyt. I'm sure it would cause more butterflies but that's just what I see looking at all of this. Maybe a different Democrat running in 84 against Reagan like Gary Hart or even Ted Kennedy, though I don't see the latter if he doesn't get the boost from challenging Carter.
