Nixon can paint Humphrey as an unrepentant New Dealer. As Jack Kennedy himself put it: "many in the business community object to his extremism." IOTL both Nixon and Kennedy (in both elections) were centrists, Humphrey's easier to slam on ideological grounds. Nixon in '60 is far more likely to do this. Also, in the debates, even if Nixon has a bad makeup day, it won't matter because Humphrey is even less telegenic than Nixon.