Hey everyone! First time poster here!
It seems like that rust is worse than it looks at first glance. Other than the chip on the top edge, there also appears to be bubbling on the upper left corner of the windshield (to the right in the picture). I would also be willing to bet that there was very little paint applied where the windshield molding rests from the factory, and the last of that is starting to fail with vibration and rock damage.
Also, check the rest of the windshield edges for more bubbling and missing paint.
Taking it to a bodyshop is probably the best way to handle it. Even the best rattlecan and touchup paint markers out there can't hold a candle to automotive paint with hardener. With time, off-the-shelf quality paint will start to become oxidized and chalky long before the OEM paint does, and will always be softer and more vulnerable to further damage. Depending on the bodyshop, you could have it professionally done for less than paint, equipment, and even your time would cost to do it yourself, and the repair will last as long as the rest of the paint does, if not longer.
Depending on how old your vehicle is, the damage might be covered by the manufacturer paint warranty, which would mean being touched up at the dealer or a manufacturer-certified bodyshop.