Yes you can add home screens. The max. home screens you can have with nova prime is 9 home screens.
To add home screens with nova prime :
Nova Settings>Desktop>Home Screens> and click on the little (+) icon in the top right hand corner of that screen .As mentioned the max is 9 screens .
To remove screens
Nova Settings>Desktop>Home Screens> just drag the screen to the top center where it turns red and will be deleted