Pronunciation: [nˈa͡ɪsɪz] (IPA)
Correct spelling for the English word "Nyseys" is [nˈa͡ɪsɪz], [nˈaɪsɪz], [n_ˈaɪ_s_ɪ_z] (IPA phonetic alphabet).
Correct spelling for Nyseys