The Nigerian Salafi Discourse Corpus (NSDC) is a purpose-built corpus of 5,791 Facebook posts (2,485,963 words; 2,518,453 tagged tokens; 149,431 sentences) published by Nigerian pages and profiles between 2015 and 2025. The corpus was assembled from eight keyword-filtered exports of the Meta Content Library (Salafis, Salafism, Salafiyyah, Ahlus-Sunnah, Sunni, Wahabism, Wahabiyyah, Salafool) and processed through a fully documented, machine-verified pipeline: schema validation, three-pass deduplication, Unicode normalisation and script-based noise removal, SGML-annotated corpus assembly, cross-keyword merging, and calendar-year segmentation. This release contains three artefacts: (1) the cleaned corpus (one UTF-8 file per post, SGML metadata tags, one sentence per line); (2) the tagged vertical corpus (Penn Treebank part-of-speech and lemma, 15 semantic fields, 15 discourse strategies), in the vertical format used by Sketch Engine and CQP; and (3) the corpus segmented by calendar year for diachronic analysis.