InGaN/GaN nanostructures form the active region of III-nitride emitters (light emitting diodes, laser diodes, single photon emitters) in the visible spectral range. In order to understand the optical performance of these nanostructures it is necessary to obtain a direct correlation of alloy distribution and optical features. With this purpose in mind, laser-assisted atom probe tomography (La-APT) is a unique tool to visualize the three-dimensional distribution of chemical species at the nanometer scale. Recent advances in this technique also offer the possibility of recording simultaneously the photoluminescence spectrum of the