In the outer-loop Bode editor plot, increase the gain by dragging the magnitude response.
Since the loops are decoupled, the inner-loop Bode editor plot does not change.
You can now complete the design of the inner loop without the effect of the outer loop and
simultaneously design the outer loop while taking the effect of the inner loop into
account.
Tune Compensators
Control System Designer contains several methods tuning a control system:
Cascaded Multiloop Feedback Design