>>16729684As a general rule of thumb, you see chaotic behavior in the regimes where the dominant interactions are 'collisions' between similarly-massed objects.
For example, you don't see chaotic interactions between most of the planets in our solar system, because their interactions between one another are perturbatory compared to the interactions between all of those planets and the sun, but you do see chaotic interactions between some groups of moons in some planets where the interactions between the moons with each other becomes significant compared to the interactions between the moons and the planet they're orbiting - Hyperion, Titan, and Saturn, as I recall, behave as a nonperturbative three-body system (at least for the moons), and I think the moons of Pluto are believed to be a chaotic system as well. With stars, you don't really see much chaotic behavior between stars in lower density regions the way you do closer to the centers of galaxies.
It's just like turbulence in fluids - all fluids are subject to the same kinds of nonlinear interactions that lead to turbulence, but that doesn't mean that all fluid behaviors result in turbulence. The study of what conditions a nonlinear system needs to meet to become chaotic, or how to measure 'chaoticity' is a whole subfield in mathematics and physics.