chomik is available in a dual-license way. The Open Source license for chomik is GPL 3.0 (or any later, at your option). You can read about it at https://en.wikipedia.org/wiki/GNU_General_Public_License.
For the commercial purposes you will need a commercial license for chomik. For the single persons (single game developers, new Chomik-based dialects single developers) it is very, very cheap. Feel free to contact me (pawel.f.biernacki@gmail.com) to agree upon it. Please use the mail title "chomik license" and describe shortly what you are going to do with chomik.
Due to the fact that the PlayyfairDisplay fonts included in sdl_chomik have a license of their own you may not use sdl_chomik commercially, even if you have the commercial license for chomik. There are multiple possible solutions to this. You can remove the fonts from your product, you can get a commercial license for the fonts from their owner, or you can replace them with the fonts you are licensed to use. The PlayfairDisplay fonts owner & license info:
Copyright (c) 2010-2012 by Claus Eggers Sørensen (es@forthehearts.net), with Reserved Font Name 'Playfair' This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is available with a FAQ at: http://scripts.sil.org/OFL