[en] Nonleptonic and weak nonleptonic decays of etasub(c) in chiral theory are considered. The lagrangian of a strong interaction is taken to be invariant under the SU(4) x SU(4) group. Symmetry breaking is chosen according to the simplest representation of (4,4sup(*)) + (4sub(*),4) of the SU(4) x SU(4) group. The lagrangian of a weak interaction is taken in the ''current x current'' form and satisfies exactly the rule of |ΔI| = 1 in ''ideal'' case of THETAsub(c) = 0. Among nonleptonic decays of etasub(c) dominate those going over isospin breaking. Among weak nonleptonic decays dominate decays to D⁰K⁰, F⁺π^-, K^-π⁺D⁰, D⁺π^- K⁰. An explicit form of meson matrix for the SU(4) group is extracted