​Gallium Nitride (GaN), along with other III-Nitrides, is attractive for optoelectronic and electronic applications due to its wide direct energy bandgap, as well as high thermal stability. GaN is transparent over a wide wavelength range from infra-red to the visible band, which makes it suitable for lasers and LEDs. It is also expected to be a suitable candidate for integrated nonlinear photonic circuits for a wide range of applications from all-optical signal processing to quantum computing and on-chip wavelength conversion. Despite its abundant use in commercial devices, there is still need for suitable substrate materials to reduce high densities of threading dislocations (TDs) and other structural defects like stacking faults, and grain boundaries. All these defects degrade the optical quality of the epi-grown GaN layer as they act as non-radiative recombination centers. In this work, we propose GaN epitaxially grown on (-201) β-Ga₂O₃ as a suitable candidate for correlated photon pair generation, leading to on-chip quantum sources for both telecomm and visible spectrum. We also present designs for GaN waveguides to achieve efficient four-wave mixing (FWM) based on the experimental absorption and dispersion data of epitaxially grown GaN on Ga₂O₃.