I am trying to get nonpareils to stick to the sides of a dried royal icing cookie. I have tried corn syrup, thinned royal icing, and a mixture of 1/2 meringue powder and 1/2 water, they stick while it is wet but when it dries they fall off when touched. I  want them just around the edges, like a frame. the cookie has and edible image in the center of it. Any suggestions would be wonderful. thank you.

I've never done this but from all the videos I've watched they put a trim of fresh (outline consistency) RI and then sprinkle on. Good luck!
 

AYes, run a line of RI around the cookie and apply nps immediately. Outline consistency. Or lightly press the cookie into the nps.