Are the wheels of the carriage worn?
The nozzle is mounted to the heater block and forms (with the cooling body) the hotend. That hotend is mounted to a steel plate, that is refered to as the carriage. This carriage has a few excentric nuts, to which a few V-grove wheels are mounted. These wear out over time, which results in the carriage becoming "sloppy" and wobbling, resulting in the nozzle being able to be lifted. In perfect condition, the wheels should have 3 flat sides, but a well worn wheel will have deep cuts around the wheel, where the running surface is worn away by the metal. The specs of a proper "openbuilds solid V[-Slot] wheel" and a generic clone of such a wheel are so close to one another, that either work. The Ender-3 has, of its own, a clone type installed, as you might spy by the type and style of ball bearing used.
Openbuild's original wheels come about 5 USD a piece while cloned replacement wheels come at 1 € or less a piece in a package of several. In either case, they are very easy to replace. It's best to turn the excentric nuts as loose as possible before swapping over to a new set to make installation as easy as possible and prevent damage to the new wheels.