I find that utilising Stasis Wall and placing down lightning above it so that the spread out lightning gets put in stasis works, though it doesn't necessarily go in every direction. Alternatively, you could try utilising layered PBCN, one layer with a CTYPE of LIGH and another with a CTYPE of THDR to produce a sort of layering, and setting a trigger for it. It should roughly produce what you seek, as the THDR (You could probably omit the THDR CTYPE and go full LIGH CTYPE on all the layers) would break up the PBCN and fling it around all over the place before the PBCN eventually disintegrates, spreading LIGH and THDR in every direction. Another idea I have might be LIGH SNOW. I don't really know what might work or not.