A transcription corepressor activity that represses or decreases the transcription of specific gene sets via binding to a DNA-bound nuclear receptor, either on its own or as part of a complex. Nuclear receptor corepressors often act by altering chromatin structure and modifications. For example, one class of transcription nuclear receptor corepressors modifies chromatin structure through covalent modification of histones. A second class remodels the conformation of chromatin in an ATP-dependent fashion. A third class modulates interactions of DNA-bound DNA-binding transcription factors with other transcription coregulators. [ http://www.ncbi.nlm.nih.gov/pubmed/7566114 http://www.ncbi.nlm.nih.gov/pubmed/9238851 http://www.ncbi.nlm.nih.gov/pubmed/7566126 ]