I have only heard Liberals blame Nixon, they love to call it “Nixon’s War” to deflect that their guy LBJ was in charge and was a total failure.
It was LBJ’s war, Nixon just did what he could with what he was handed and considering what he was handed he did as well as can be expected.
Nixon continued the excursion for a long time after being elected (Promising to end the draft in ‘69 if elected, never happened that year). Intel was probably the primary reason because militarily we were extremely passive/only played defense in SV, there were “US Spooks†all over North Vietnam doing Intel on the USSR/China. Knew a guy who would deliver supplies in NV right in the middle of a jungle. Places he could go are described as concrete structures/some mansion and plantation types/ filled with wall-to-wall computers.