1) President Rockefeller would select Senator Howard Henry Baker to be his Vice President and thus his running mate for the 1976 Presidential Election. Senator Baker would be acceptable to both moderate and conservative wings of the Republican Party.
2) Now Rockefeller is finally President I would say he would run for the 1976 Republican Nomination and would be challenged by former Governor of California, and Gporter's hero Ronald Wilson Reagan. I would expect Rockefeller to come out on top like President Ford in RL.
I would also assume that former Governor of Georgia Jimmy Carter would run for the Democratic Nomination and win. Thanks to him being a Washington Outsider and vowing to clean up Government. I can imagine him being nominated but I doubt he'd be able to defeat President Rockefeller. Considering he has no connections to Watergate whatsoever.
My Predictions in this match up between President Rockefeller and Governor Carter.
Nelson Rockefeller/Howard Baker (R): 328 Electoral VotesJimmy Carter/Walter Mondale (D): 210 Electoral VotesWith Rockefeller being a Norteastern County Club Republican, I would expect him to carry most states in the New England area except for Massachusetts and Rhode Island. I would expect Rockfeller to carry most parts of America, expect for two states in the South (Kentucky and Tennessee, thanks to Howard Baker being his Veep) and a few in the Midwest. Them being, Illinois, Indiana, Michigan and Ohio.