Does this support NES files?
Not yet, but I'd like it to. For that we'd need to get a NES developer on board to help convert the compiler (simple enough) and engine (slightly trickier). I'd be happy to co-operate, share code (the source is freely available in the download) and write any Windows editor code required for things like sprites and graphics. If you know any NES forums where developers hang out you could try and post there to show there's enthusiasm for the tool and see if anyone's interested. If you do, let me know where you've posted and I'll come along and offer my assistance
Well I didn't post anywhere, but you can! I found a subreddit, r/NESDEV, and there you can probably ask others. I would really like to help, but I am in no way capable of doing something like this.