You can try a social story, or I think your positive reinforcement idea is worth a try! Depending on how much you think he would understand, (or how much you'd be willing to do) you can break the morning up into 10 minute segments and give him a smiley face or sticker for every 10 minutes he doesn't pick his nose. If he is able to get 6/10 stickers (or whatever goal you want to aim for) then he can have a special treat!

Good luck!

My son did that too. He liked to pick at skin as well. Like scabs and rough spots! I think he liked the texture. It's a sensory issue, and for my son it became a compulsive tick. (When we changed his diet and put him on the Methyl B-12 shots, he has stopped most of his compulsive habits.) I'm not sure if this is the same for your child as I can only speak from my experience. Perhaps you could give him a sensory object, or a toy that feels textured, to hold whenever you notice him picking his nose, something he can pick at, so that he eventually grabs that object in lieu of picking his nose?

I'm not sure it's the same motivation as sticking things up his nose is for my son but I started working with him in a distraction free 1 to 1 environment a few hours a day and over several months he just didn't need to do that anymore. Alot of kids need that 1 to 1 time whether it's in a form of therapy or just time with you. 1 to 1 time is huge for many of them.

I think it may be sensory. He starts school tomorrow, so I can check with the OT there or contact our former OT. I had to cut all private therapy due to school schedules..ugh.

Do you think it might be a sensory thing? Is he receiving any OT?