[en] Transmission electron microscopy (TEM) investigations on Nd_2/3-xLi_3xTiO₃ with x=0.14 reveal a rich variety of structural features in the samples prepared under different conditions, such as superstructures, anti-phase domains, and nano-chessboard structures. Our careful analysis shows that these structural phenomena can be fundamentally understood as the combination of structural effects of (Nd, Li)-ordering along the <001>_p direction and the spinodal decomposition along the <100>_p/<010>_p direction. The coexistence of phase separation and cation ordering can lead to visible nano-structural complexities in many crystals, as the typical results, the regular lamella structure, nano-chessboard structures and anti-phase boundaries have been extensively studied. - Graphical abstract: Transmission electron microscopy investigations on Nd_2/3-xLi_3xTiO₃ with x=0.14 reveal a rich variety of structural features in the samples prepared under different conditions, such as superstructures, anti-phase domains, one-dimensional lamella structure, nano-chessboard structures and circle-like pattern