The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double- () decay in with a target half-life sensitivity of approximately yr using kg of isotopically enriched liquid-xenon in a time projection chamber. This improvement of two orders of magnitude in sensitivity over current limits is obtained by a significant increase of the mass, the monolithic and homogeneous configuration of the active medium, and the multiparameter measurements of the interactions enabled by the time projection chamber. The detector concept and anticipated performance are presented based upon demonstrated realizable background rates.