In the eyes of Google and other search engines, your website migration to NiceJob, is essentially just a website redesign. All your history and work you've done to date (authority, links etc.) remain with your domain, they are not effected at all by moving your website to NiceJob.
Because NiceJob copywriters are also SEO professionals, the content on NiceJob sites usually results in improved Search engine results. We also spend alot of time making sure all the other On-Page SEO factors are highly optimized (load time, code base, Rich markup, etc.). So if your rankings are effected by the move, it will likely be for the better.