We don't have synonyms for nicene yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are nicee and picene.
(adj) :
Of or pertaining to the First Council of Nicaea convened by the Roman Emperor Constantine I, or to the churches that profess the Nicene Creed, the formulation of which began at this council.
(adj) :
Of or pertaining to the First Council of Nicaea convened by the Roman Emperor Constantine I, or to the churches that profess the Nicene Creed, the formulation of which began at this council.