I am trying to use JavaScript inside a Nintex Form for Office 365. When I write the code inside the Custom JavaCript block of the form settings, it works perfect. However when I use my own JavaScript file and put it into the Advanced block it doesn't work and says SP is not defined. When I look the developer tools I see that my JavaScript file is loaded before sp.js and JQuery.

Is there a way to make my JavaScript be loaded last? or solve this problem?