It has been suggested that El Ninos increase sea level rise. This is supported by this plot from the University of Colorado:
An El Nino would release warmth from the IPWP into the atmosphere. Lowering the thermosteric component of sea levels. But the plot.
Sea level rise causes El Ninos. The Pacific Ocean has a preferred temperature. If it’s too warm it will release warmth to the atmosphere.
What about sea level fall? The Pacific Ocean then tries to retain warmth causing La Ninas. This might be visualized by looking at the IPWP building warmth during La Ninas.
During La Ninas, upwelling takes some of the coldest liquid water the Ocean has and places it in an equatorial region and then as it is blown to the West the Sun warms it. And then stores it. If one were to want sea level rise, that is how you’d do it. Take stuff that will expand the most and give it lots of Sun.