We present a method for designing quantum light sources, emitting in the visible band, using wurtzite InxGa1−xN quantum dots (QDs) in a GaN matrix. This system is significantly more versatile than previously proposed arsenide and phosphide based QDs, having a tuning range exceeding 1 eV. The quantum mechanical configuration interaction method, capturing the fermionic nature of electrons and associated quantum effects explicitly, is used to find shapes and compositions of dots to maximize the excitonic dipole matrix element, and optimise the biexciton binding energy. These results provide QD morphologies tailored for either bright single photon emission or entangled photon pair emission, at any given wavelength in the visible spectrum.