Scopes are really difficult to buy for someone else. Kinda like a watch. If you give one to someone, they will like it, but is it really what they want?
The low dollar scopes all have mediocre reticles. Some will hold zero and some won't. I spent many years and too much money on cheap scopes. I won't do it anymore.
The least expensive scope I'll recommend is the Hi-Lux CMR 1-4x24 which is about $350. I have one and it has been good. Holds zero and the turrets can be finger adjusted. If you adjust them and then go back to zero, the scope still holds zero.
If your son is serious about shooting, don't waste your time with cheap scopes. That includes the Nikon scopes. They're OK and he'll be happy if he never tries anything else. But I think it's worth it to get a good one the first time. Good glass isn't cheap.
One more thing. Just because a scope has the same brand name doesn't make it the same quality. Case in point, Vortex. Vortex makes a full range of scopes. As inexpensive as $80 all the way to over $2K. The $80 scope, even though it's made by a quality company like Vortex, is still a cheap scope.
Take your time. Do your research. Get the right one the first time.