it is my understanding that it is a measure of the randomness and chaos of particles in as system
There are many different kinds of entropy. "Measure of chaos" is very inaccurate characterization of all of them.
Second law of thermodynamics has consequences for changes in macroscopic bodies that can attain thermodynamic equilibrium state and thus be ascribed thermodynamic entropy - this is meaningful only for systems in thermodynamic equilibrium.
Thermodynamic equilibrium of body is a situation where macroscopic observations detect no macroscopic motions, no changes, no transfer of energy. Moreover, to apply thermodynamic theory to the system, its equilibrium state must be accessible to the system given external constraints. For gas, this means it has to be in a closed container, otherwise it will spread everywhere.
Universe is hardly such a system, for we know of no constraints to its volume or energy ; and thus there are no thermodynamic state variables entropy could be function of.
Universe has never been experimentally probed in such a way as air or steam in heat engines. To claim it is in thermodynamic equilibrium and can be ascribed thermodynamic entropy is unfounded. It is also meaningless to claim the whole universe obeys 2nd law of thermodynamics, when nobody has ever observed heat transfer between the universe and the reservoir and define temperature of the universe. Using 2nd law in such grand scenarios is a patently unfounded extrapolation of our experience with systems of size comparable to humans. In the whole universe, there is gravity and other things mostly ignored in all experiments on which thermodynamic theory was founded.