following should do the trick

var ppobj = new NF.PeoplePickerApi('#'+PP);
ppobj.clear();‍‍

see  

Hello Marian,

Thanks for your answer, shame on me, to be honest I don’t have a lot of knowledge on Nintex, could you please give me more details about this, I mean where should I declare the code.

Thanks

Walter Fuentes

since you want to trigger the clear on checkbox change, you have to define (on)change event handler for that checkbox control.

these kind of handlers are typically being attcahed in ready() or RegisterAfterReady() events.

you can place all the handling javascript code into form settings/custom javascript section or place it into separate script file and include the file within form settings/adanced section

Hello Marian Hatala‌

Thank you very much for the extra help you gave me, my problem has been fixed

that's great!

set the question answered.