  The origin of the breaking of conventional linear k_\perp-factorization for
hard processes in a nuclear environment is by now well established. The
realization of the nonlinear nuclear k_\perp-factorization which emerges
instead was found to change from one jet observable to another. Here we report
on an important technical progress, the evaluation of the four-gluon color
dipole cross section operator. It describes the coupled seven-channel
non-Abelian intranuclear evolution of the four-gluon color-singlet states. An
exact diagonalization of this seven-channel problem is possible for large
number of colors N_c and allows a formulation of nonlinear
k_\perp-factorization for production of gluon-gluon dijets. The momentum
spectra for dijets in all possible color representations are reported in the
form of explicit quadratures in terms of the collective nuclear unintegrated
glue. Our results fully corroborate the concept of universality classes.
