Abstract: Complex oxides are a fascinating class of materials that exhibit the full spectrum of physical phenomena: superconductivity, magnetism, quantum phase transitions, and more. Moreover, the correlated interplay between structural, charge, spin, and orbital degrees of freedom in these systems opens up the possibility of inducing and controlling exotic phenomena using state-of-the-art atomic layering techniques. In this talk, I describe the engineering of electronic structure and transport properties of complex oxides. Specifically, I focus on our ability to manipulate the orbital configuration in rare-earth nickelates with atomically-precise heterostructures using molecular beam epitaxy. A combination of first-principles theory and synchrotronbased x-ray techniques reveal that unique three-component heterostructuring can be used to effectively change the nickelate orbital structure to emulate that of the high-temperature superconducting cuprates, and, in fact, can tune the orbital configuration between the bulk structures. The approach is based on simple physical mechanisms and represents a potential route to explore and enhance a wide variety of orbitallydependent phenomena including metal-insulator transitions, spin switching and superconductivity.