We consider two cases!
1. When the point is outside the sphere
The whole charge on the sphere can be considered as to be concentrated at a single point and hence acts like a point charge. The electric potential at any point p distant r from the point charge is V = kQ/r. So the potential of the non-uniformly charged sphere can be the same as that of a point charge.
2. When the point is inside the sphere
When the point is inside the sphere, the unevenly distributed charge on the surface of the sphere cannot be considered as point charge. The electric intensity due to different charges on the surface of the sphere will have different values on a certain point inside it. There would be a resultant E on various points in the sphere. Since V = Er, therefore, V would also have different values at different points inside the sphere.