Pure Chaos it not an energy attack - it is lack of reality. It does not inflict damages by itself. Coming apart at seams due to lack of anything to keep you real does.
Anyway, Pure Chaos is a fun idea to play with. Mainly due to fact, that if it is pure chaos then all sizes and dimensions within cease to matter.
You can create sphere of pure chaos size of a fist, and then with some luck put your whole arm inside, without it ending out out other side of the sphere (assuming that arm did not change into mini-tentacle, or something simillar). You can create sphere of pure chaos size of a horse, throw someone inside, and with some luck have him try to get out for subjective year, crossing what it feels like thousand miles.
My proposition would be something like that:
Something like that can be useful for very wide array of things, and developed in very large array of ways. It could be used as a weapon - as few have active defence against shaping. As a way to get magical components - Wyld mutates, and created wonders. Quite a few of them can remains after charms is done.
Good follow-up would be a charm that gives some authority over affected area. It's not possible to truly control chaos, but it should be doable to give it a theme to follow.
It can be a weapon. A way to create quasi-sorcerous effects. It can be used to create things. Etc.
More advanced charms could tie small sphere of Pure Chaos to a hand, or to an end of a weapon. With correct theme, it could destroy close to anything.
All that is balanced with the fact, that shaping defence is relatively easy to get... Though is someone with perfect shaping defence enters sphere of Chaos bound to the theme of being bigger-on-inside labyrinth, then shaping defence will not help that person all that much.
Other way to develop it is transportation. You have two spheres of Pure Chaos. Inside the distances, sizes and dimensions have no meaning. It is possible that You can enter one sphere, and exit another, regardless how far they are in Creation. It would require speficic charm probably, but hey, Oramus. It is his domain after all.