Ancient subscription traditions and standard conciliar histories report that only Secundus of Ptolemais and Theonas of Marmarica finally refused the Nicene creed. Whatever exact attendance figure is used, that is not a one-vote decision. Eusebius of Caesarea’s letter to his church explains his own acceptance of the council’s creed after discussion of its terms.
The honest version includes what happened next. Arian and semi-Arian parties remained powerful, imperial policy shifted, some bishops changed positions, and Athanasius endured repeated exile. Nicaea was neither a fabricated unanimity nor the end of theological conflict. It was, however, an overwhelmingly adopted settlement—not a cinematic 51–49 vote that suddenly created Christ’s divinity.
Primary source
Eusebius of Caesarea, Letter on the Creed of Nicaea: https://earlychurchtexts.com/public/eusebius_letter_to_his_church_about_nicaea.htm