Vadim posted a solution that provides Captcha functionality in a local or O365 Nintex implementation, however I cannot make it work in Nintex Live. Are there special considerations to make it work there?
it's something we are looking into. Can you please put your votes in on this feature request, here : Captcha for Forms – Customer Feedback for Nintex
Also, add a comment to it, as that will help also. UserVoice is what our teams use to help with understanding what our customers are asking for.