First question is why on earth would you want to.
It's nutrasweet right? So that's basically aspartame.
I don't know of many (any) that have been confirmed to contain aspartame as a sweetener. Most use sucralose, and some liquid stevia and Ethyl Maltol.
You might want to check the
e-liquid section, there is a DIY specific forum there - they will know better than I. You will need 5 posts or more here to ask your question, but you can read posts over there with fewer.
DIY E-Liquid