Final answer:
Nussbaum is indicating that the most engaging stories are those of marginalized groups exerting influence in spite of their lower status, relating to the struggles and narrative tension found within certain literary works.
Step-by-step explanation:
When Nussbaum refers to "the most compelling plots remain those of the subalterns, who are faced to wield power from below," she is discussing characters and groups who lack traditional social or political power but endeavor to assert themselves despite these constraints. This statement relates to social or political groups marginalized and oppressed by the dominant culture. These groups or characters, often central in Naturalistic novels and critical theories such as New Historicism or Feminist Criticism, face challenges due to systemic inequities such as gender, class, or ethnicity. Their stories are seen as 'compelling' because they illustrate the struggle to overcome external forces and internal limitations, often within an oppressive society where the laws of nature and societal norms work against them. The tension between these subaltern characters and the dominant groups creates a dynamic and significant narrative in literature.