How can I shrink these Nike shorts?

I bought these nike shorts and it’s a bit too big, it’s 100% polyester if that helps….

If you shrink it in the dryer, the fabric may run and make it look old.
I don’t think there’s a way except to return it and get a smaller size.

IF they are made of cotton, maybe. Wash in very hot water and put in a very hot dryer longer than necessary to dry. If they are made of man made material, your option is to gain weight.

wash with fabric softener then dry for a bout 20 minutes

you can take it to the Tailor shop to fix