The mother scolded her for being late to dinner.

Literal

Mother [topic-は] she [subject-が] dinner [to-に] was-late thing [object-を] scolded

彼女が夕食に遅れたこと — the nominalized clause 'the fact that she was late to dinner' serves as the object of しかる (to scold). こと turns the entire clause into a noun phrase.