  Topological nodal superconductors are generally realized based on
unconventional pairings. In this work, we propose a minimal model to realize
these topological nodal phases with only $s$-wave interaction. In our model the
linear and quadratic spin-orbit couplings along the two directions break the
isotropy in momentum space and introduce effective unconventional pairings on
the Fermi surface. This model may support different nodal superconducting
phases characterized by either winding number in BDI class or Pfaffian in D
class at the particle-hole invariant axes. In the vicinity of the nodal points
the effective Hamiltonian can be described by either type-I or type-II Dirac
equation; and the crossover between these two nodal points can be driven by
external Zeeman fields. We show that these nodal phases are robust against weak
disorders, thus are possible to be realized in experiments with real materials.
The smoking-gun evidences to verify these phases based on scanning tunneling
spectroscopy are also briefly discussed.
