Unfortunately, there is no iPad version as of current so you get the iPhone version which lets you expand a little but its not the same. Until Cortex Control supports the Nano (if it ever does), the app is the only way to edit excluding using the Nano controls directly etc.
Actually or me, with my small iPhone 12 mini I actually find using the app on my iPad okay. Yeh zoomed in it doesn’t look perfect, but very usable and actually better than on my iPhone.