That's a pretty broad question which I don't think has a single answer. I can say that El Nino years correlate with fewer/weaker tropical storms/hurricanes, especially those that originate during the "Cape Verde Season" off the African coast. El Nino tends to suppress the eastern trade winds by introducing SW'ly wind shear in the tropical Atlantic basin. Wind shear is a hurricane killer. So, from a big wave groundswell perspective, El Nino years tend not to be great.
La Nina would tend to have the opposite effect, but there are many other synoptic variables that impact local surfing conditions in any given area.
El Nino tends to reverse the trade winds in the pacific causing warmer water to get pushed up against the west coast and results in more hurricanes and tropical storms there but doesn't have an effect on us in the atlantic.