I am finally getting into using nurtures and unfortunately ran into a bug (see below in case you are having the problem).
So now I have to recreate the nurture. 
Is there a way to use an email I already created as part of this nurture, or one I created using EMB 2.0? Doing it on the fly while working on the nurture is not the best experience.
It looks like this nurture is running into an issue that has recently been reported. The records are not getting added to the nurture and on the back end it does not appear that they are processing. It seems like they are not going to get added for some reason.
I have linked this case to the defect #88325 (https://portal.sugarondemand.com/#supp_Bugs/88325).
Currently the alternative option appears to be to deactivate the current nurture and recreate a new nurture. For now this is the best available option until the defect is resolved.