Oh I'm certain it can track and destroy an incoming tank round...once...
But the rate of fire for the laser is probably much less than the rate of fire a standard MBT can achieve
For example: the Airborne Laser System (ALS) is the size of a 747 not because the laser itself is that big, but because the heat management systems and the energy storage systems are that big.
Now granted the ALS can get off a handfull of shots each powerfull enough to destroy a missile but that is all possible
because of the large energy storage and heat management systems, and once it does deplete it's stored reserves of energy and/or maxes out its heat dumping capabilities it cannot fire for a very long period of time when compared to how fast events can happen on a battlefield. To sum up, laser weapon systems the size of MBTs are absolutely possible, but because of the size limitations of a MBT chassis these laser MBTs will be severely limited in their rate of fire ability
or they will require some kind of secondary support vehicle to be hooked up to help make them a viable threat with today's energy storage and heat sink tech. But who really knows, R&D is happening all the time; maybe a new super high capacity yet physically small energy storage device is right around the corner.
Personally, I think we will start to see laser weapons on the battle field within our lifetime, but they will not be the main assault weapons. Instead they will play a very strong support role. As it is now they are being developed more as anti-air or CWIS type weapon systems, and I think this will be their most viable route.