That depends; it could be either redundant or contradictory. If I understand it correctly, "stochastic" only means that it's governed by a probability distribution but not which kind and there are lots of different kinds: https://en.wikipedia.org/wiki/List_of_probability_distributi... . It's redundant for a continuous uniform distribution where all outcomes are equally probable but for other distributions with varying levels of predictability, "stochastic chaos" gets more and more contradictory.