This often appears in the hyphenated form
god-sent. And sometimes it's written with a capital
G. But it is listed as
godsent in the online Merriam-Webster, Dictionary.com and Wiktionary.
Usage examples are fairly thin on the ground. An example from last month on the Indian media industry site exchange4media.com was in an article headed "Why '21 days of isolation' is an opportunity for personal growth", with the subtitle
Guest Column: Mahesh Chauhan, Director of Salt Brand Solutions, believes that our current phase of self-isolation is a godsent opportunity for introspection and personal growth
I'll add
godsent as a rare word.