Is it possible to get a long term developer licensed copy of Nintex 2013 for workflows and Forms to use in a CloudShare SharePoint 2016 instance online?
I do not think so. I have always used trial versions which should last you for 30 days.
I beleive, if you become a partner, you will have some of these advantages.
Currently the Nintex licence model has not Developer licenses. Licences for non productive servers are covered by software assurance and/or premium support.
Currently development licenses are issued in conjunction with production licenses for customers with certain support options. If you worked at a partner organization, there may be other methods for using Nintex internally that could be looked into.
As for getting a 2016 license, that is not possible because we haven't release Nintex for SharePoint 2016 yet; therefore, there isn't a license or product key to provide for you to use.
Let me know if you have any questions.
Is this on your roadmap, I believe Nintex should have some licensing model for developers, something that is also more affordable so that it could be used for development purposes and may be use it for some demo as well?