It'd probably hurt Nixon, siphoning off his support in the Deep South, which would coalesce around Wallace. It might help a bit in the Northeast, but not by much; though he was supported by many in the Rockefeller wing of the party, Fong wasn't well-known on the national stage. Recorded video is hard to come by, but he's definitely not going to have the impact the border-state firebrand Agnew did. Before the tax evasion scandals came out, many viewed him as next-in-line to Nixon, and like Connelly was supported by both the conservative wing of the party while the Rockefeller wing still would have held their nose for him.
Nixon: 287
Humphrey: 174
Wallace: 77