We study the behavior of quantum invariants in the integrable maser model, and in the nonintegrable case, where the constants of motion are destroyed by turning on an interaction which is known to be classically chaos generating. By plotting the mean values of selected observables for each individual eigenstate of the energy against the energy eigenvalues, we found a way of showing and visualizing quantum manifestations of Hamiltonian chaos in the present model, which, in particular, allowed us to have a measure of how much each group of individual eigenstate differs from the integrable situation.21241732299307