This dataset contains process-based model simulations of nitrous oxide (N2O) emissions and production from natural terrestrial ecosystems across northern high latitudes under baseline and permafrost-thaw conditions. Simulations cover northern high-latitude terrestrial ecosystems from 1969 to 2019 at a spatial resolution of 0.5-degree x 0.5-degree. Annual gridded outputs are reported in units of mg N m-2 yr-1. The dataset was generated using the Terrestrial Ecosystem Model (TEM), a process-based biogeochemical model that explicitly represents terrestrial carbon and nitrogen cycling and incorporates permafrost-related processes. Two simulation scenarios are included: a baseline simulation and a permafrost-thaw simulation. For each scenario, annual gridded outputs include summed N2O net emissions and summed N2O production. The dataset provides information on the spatial and temporal patterns of N2O responses to permafrost degradation and can support studies of nitrogen cycling, ecosystem-climate interactions, climate feedbacks, and model intercomparison analyses. The data are provided in comma-separated values (CSV) format.