That settles that.
落户 is “settled” in the sense of finding a place to live (the 户 pertains to households). I don’t think it means “to settle (a matter)”. See ChatGPT’s explanation:
这是落户。 This is a sentence in Mandarin Chinese, which can be translated literally into “This is getting a household registration”.
I think “that settles that” (used for those situations where something has led to a swift conclusion of a matter) doesn’t easily translate into Chinese. Maybe it could be 就这样解决了 or 就那样办完了 or multiple other things.