Though NbO2and VO2both exhibit similar electrostructural phase transitions, alloying the two completely suppresses ordering of either kind. It is mostly accepted that impurity ions act as electron-localizing defects, which weaken ordering in a percolative manner. This work reports total X-ray scattering measurements across the NbxV1–xO2phase diagram that challenge this prevailing notion. The observations are instead more consistent with the geometric frustration of displacement models recently used to explain the suppression of long-range structural order in the V1–xMoxO2phase diagram. Two separate short-range ordered phases are observed in the NbxV1–xO2phase diagram, one of which has not been observed before. The structure of this new phase was not determined in the present study, and it is provisionally named 2D-u to indicate that the phase is likely two-dimensional and that it is unknown whether it is a new or existing structure. The other phase, stabilized around 10% Nb substitution, is shown to be structurally equivalent to the 2D-M2 phase that appears at or above 19% Mo substitution, except that it coincides with the insulator side of a metal-to-insulator transition (MIT), while the Mo analog does not. This shows that the MIT intrinsic to VO2can persist into the quasi-two-dimensionally ordered state.