Correct. There are lots of nations which just use their national flags as ensigns, so imho the criteria don't need relaxing - there are loads of possibilities. I specifically kept it to ensigns and didn't mention jacks so that nations which have a separate jack but use their national flag as ensign are still eligible.The goal as I understand it is to design an ensign for a nation that only uses its national flag or distortion thereof.
Having said all of that, since the entry by @Green Painting is the only one so far, and because of the outage today, I'm extending the submissions period for a week, as per Rule 4. I've amended the Challenge Post accordingly, both here and in the Challenges thread.