Photography is kind of like an instrument here, what's the budget? That's probably the better starting question... I have a D5600 that looks like it's just a little above the one she has in features. Given photography is in a bit of a transition point potentially to mirrorless cameras (still pretty pricey) it might be a good idea to hold off upgrading the body. Also, if she's going to do Photography in college there may be a need for a film camera? (I don't know if traditional techniques are still being taught, but there's a lot of value in learning black and white photography/developing for skills) If she has any idea where she wants to go yet you might dig through their course catalog and see if it's all digital or not.

The big thing is with what she has she can already do manual adjustments of aperture, shutter, etc. You could just spring for a nicer lens or two, especially if she wants to do sports photography. Having a lens that can maintain a large (low) aperture all the way through a long length would help her for that. Regardless of route, I'd stick with Nikon since the lenses are interchangeable generally.

If you're looking around $1k the D7500 might be a nice upgrade. If you're willing to go more then the D750 would be the next level up with a mirror still. At $2k you can break into the lower level mirrorless with a Z5 or Z6 kit. Check out BHPhotoVideo for some decent deals. Amazon does well too, as well as sometimes Costco and Sam's Club.