  We compute single-particle energy spectra for a one-body hamiltonian
consisting of a two-dimensional deformed harmonic oscillator potential, the
Rashba spin-orbit coupling and the Zeeman term. To investigate the statistical
properties of the obtained spectra as functions of deformation, spin-orbit and
Zeeman strengths we examine the distributions of the nearest neighbor spacings.
We find that the shapes of these distributions depend strongly on the three
potential parameters. We show that the obtained shapes in some cases can be
well approximated with the standard Poisson, Brody and Wigner distributions.
The Brody and Wigner distributions characterize irregular motion and help
identify quantum chaotic systems. We present a special choices of deformation
and spin-orbit strengths without the Zeeman term which provide a fair
reproduction of the fourth-power repelling Wigner distribution. By adding the
Zeeman field we can reproduce a Brody distribution, which is known to describe
a transition between the Poisson and linear Wigner distributions.
