Hi Oran,
We have a provider model for editors, you would have to implement a provider in a class library project and compile it into a dll that goes in the bin folder, then you can configure it to be available from mojoEditor.config file.
You can study the code for existing editor providers to learn how to implement it.
I had not heard of nicEdit before, it appears to be open source but it does not look like it has been updated since 2008 and it is not very feature rich. Just wondering what it is you like about this editor?
Best,
Joe