I like it prn. an-TONE-yah or an-TONE-ee-ah but not an-toe-NEE-ah, particularly. Noa doesn't seem a logical nn for it, but it's not totally off-the-wall (like, say, Antonia nn Jessie :b).
I love Antonia! I don't particularly like any of the nns for Antonia so I am glad you came up with Noa. The only other nns I can think of (that I even remotely like) are:Ana Nyah Antie Onia