Active colloids in nematic liquid crystals are exciting vehicles for materials manipulation. Colloid shape, surface chemistry and dynamic displacement can be designed to introduce defects whose non-linear dynamics generate new modalities of motion and interaction. These effects rely on energy conversion mechanisms, in which active colloids with tailored surface functionalization and shape seed defects and distortions in the nematic liquid crystal domain. Once the colloid moves, e.g., under the action of an external field, these defects undergo complex, non-linear rearrangements with implications for colloid motion. Interactions emerge that differ strikingly in range and form from their static counterparts. I describe our current state of understanding of these systems, their application and our vision for future work in the domain. These interactions provide a rich toolkit for hybrid top-down, bottom-up assembly schemes in which microrobots based on active nematic colloids exploit these far-from-equilibrium topological structures as tools for micro-robotic tasks including building and reconfiguring structures.