Use the Filter > Render > Difference Clouds technique (common in Photoshop/GIMP/Photopea) on a black layer, followed by Invert and adjusting Levels to create jagged lightning veins. You would then use a Hue/Saturation adjustment to color it blue.
You can also achieve a similar effect by generating a noise texture and then applying a Threshold or Levels adjustment to sharpen the lines. After that, use Gaussian Blur slightly and re-adjust Levels to control the thickness. Blending modes like Screen or Linear Dodge (Add) work well on dark backgrounds, especially for lightning-style effects. orbit beats
