Novak stated that had McGovern not initially picked Eagleton as his running mate only to unceremoniously dump him 3 days later, the election of 1972 may not have been such a massive landslide.
Oh it would still be a landslide alright, once McGovern's in that's a certainty. But without Eagleton, McGovern might be able to pick up a few more states. Minnesota and Rhode Island seem safe as they were close in OTL. Perhaps a few more traditionally Democratic States stay that way in 1972?
Assuming that Nader acquits himself well during the campaign and is able to successfully mobilize a portion of the youth vote, I could definitely see him running (successfully) for a seat in the House of Representatives or the Senate in 1974.