Hi is it ok if I made a new chapter of already existing VN and submit it as a second file for that project, so its easy to know where my submicion starts and end.

We do accept DLC and Fandisc style content to be submitted to the jam, which we couod easily extend to new chapters, however I'd apply the same ruling to the question here; https://itch.io/post/4185256

This means there would be an expectation that you would be recreating sprites and using only a limited amount of things from your prior chapters.