Yeah, nuclear provides a steady base load, so the percentage goes up or down depending on overall grid utilization. Right now its doing 2.28 MW [0], which is more than what Wikipedia claims as its "Nameplace capacity" of 2.256 MW [1].

0. https://www.gridstatus.io/live/caiso

1. https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant

The correct unit is GW.