Hi, i think what catnapper suggested are very good ideas. Your little baby really needs to go to "school" and to get to know other pupils as well.
I would also suggest not to stare at him and say no, just put him away, say no digging, and give him a command he already knows. As soon as he follows it, praise him or give him a treat. This can take a while, so be prepared to do it again and again, give him time to understand what you want him to do. So as soon as he starts digging, put him away, say no digging, give him a command and praise him, that is my suggestion. And a very important point is to have him trained at a professional puppy class.
All the best for your little digger and you
Michael