The word "chaos" in scientific and mathematics refers to sensitivity of time evolution of a system to initial conditions. Change a few small things, and then larger scale things can change as well later on.
Also, "linear" and "non-linear" have specific mathematical meanings in science.
See:
Linear Function -- from Wolfram MathWorld
Linear Operator -- from Wolfram MathWorld
Linear Transformation -- from Wolfram MathWorld
Notice the similarities? There is a notion of
superposition that is characteristic of linearity as is the notion of
homogeneity.
Chaos Theory happens to be a very large part of the study of non-linear dynamics (dynamics that are described by functions that don't follow the super position principle or homogeneity).
I'm not sure what is so controversial about what he said. Perhaps when embedded in some political debate, things take on different meaning. But the notions of linearity and chaos have been established for quite some time in science and mathematics.