I optimized a geometry of $\ce{Ni(H2O)6}$ using quantum chemistry and got a molecule which is symmetrical for the $\ce{Ni-O}$ distances as shown here:
In the literature it says that this complex has an $\ce{O_h}$ point group, but this complex looks like it is $\ce{T_h}$. Do I need to revise my group theory or is what I am looking at actually a $\ce{T_h}$ point group?