To jump onto the box you need a theoretical vertical velocity of 3.62 m/s [v=square root(2*g*box height)] with g - gravity acceleration 9.81 m/sē
Therefore, you need a vertical linear momentum of p=272 Ns [p=m*v] to accelerate the COM
Your maximum ground reaction force depends on the type (squat or countermovement) and duration of the jump and the shape of the force curve.
In case of a rectangular shape and a duration of 0.3s your vertical ground reaction force is 1642 N [F=p/s+m*g]

I have attached a file with the calculation and a typically force of a countermovement jump

Christian