  We investigate the states of triplet pairing in a candidate nematic
superconductor versus typical material parameters, using the mean field theory
for two- and three-dimensional tight-binding models with local triplet pairing
in the $E_u$ representation. In the two-dimensional model, the system favors
the fully gapped chiral state for weaker warping or lower filling level, while
a nodal and nematic $\Delta_{4x}$ state is favorable for stronger warping or
higher filling, with the $d$-vector aligned along the principle axis. In the
presence of lattice distortion, relative elongation along one of the principle
axes, ${\bf a}$, tends to rotate the nematic $d$-vector orthogonal to ${\bf
a}$, resulting in the nematic $\Delta_{4y}$ state at sufficient elongation.
Three-dimensionality is seen to suppress the chiral state in favor of the
nematic ones. Our results may explain the variety in the probed direction of
the $d$-vector in existing experiments.
