Let X(t) = (X 1 (t), . . . , X d (t)), t ∈ [0, S] be a Gaussian vector process and let g(x), x ∈ R d be a continuous homogeneous function. In this paper we are concerned with the exact tail asymptotics of the chaos process g(X(t)) + h(t), t ∈ [0, S] with trend function h. Both scenarios X(t) is locally-stationary and X(t) is non-stationary are considered. Important examples include the product of Gaussian processes and chi-processes.