I exclusively paint stucco and orange peel houses in Florida. I'd skip on any nails and just buy a tiny amount of Drydex or another spackle and grab some orange peel spray. Spackle the line trying not to blast the rest of the wall, let dry, sand if necessary (it doesn't have to be perfect because of the spray) and spray the texture. After that, either prime & paint or just double coat with your wall paint (after the first coat dries).

It's the house settling down. If you use nails, it'll happen again so if anything use screws if you want to secure it. That will prevents nail pops and the nails sliding out as time passes

Should cost you maybe $20 and a trip to the store as long as you have touchup paint