Model stopped shortly into Step 3. Here is the Force-Displacement curve for pushing one-quarter of a clip into the plug. Multiple this value by 4 to get the full model reaction force.

The force that is shown above is not real, it is an artifact of using linear elastic materials in a model that takes them past their point of failure. Therefore if the clip would have broken. 

The maximum tensile strength of Pure Nickel that I found was 1000 MPa, which has been colored red below, and the yield strength was 935 MPa. Annealed Nickel had much lower values.  It is difficult to find the ultimate tensile strength for silicon, but one reference was 120 MPa.

If your goal is that this clip does not break off, then you are bending it too much and you should consider a design change.