Hmmm....this sounds like folk etymology to me. I've seen some old maps -- dang, I don't know if I still have the book or not -- I'll have to look for it -- anyway, instead of "America," the map says "Nova India" -- Latin for "New India."
In Deos -- Hmmm....in Latin this would be gods, accusative plural rather than In Deis, ablative plural. In plus accusative is "into," compared to in plus ablative, which is "in."
Whatever ... it still is the fact that India was referred to as Hindustan in the 1400's ... my Latin is not up to your expertise ... but what Columbus conveyed to his sponsors was that the locals were "in god" or indeos ... however that translates out ..... as Indian ... today ...