Hi,
Add two user roles to your form as Approver and Viewer.
You are using two views in the form. Consider View1 can able to view by Viewer and approver can able to view the view1 and view2.
Add one button in the view1 page to switch to view2.
Add following conditional formatting on the button,
“User’s current role” is not equal to “Approver” then hide this control.
Now viewer cannot able to switch to the view2.