valor-software/ng2-bootstrap

<button type="button" class="btn btn-primary" (click)="openModal(template)">Open first modal</button>

<ng-template #template>
  <div class="modal-header">
    <h4 class="modal-title pull-left">First modal</h4>
    <button type="button" class="close pull-right" aria-label="Close" (click)="modalRef.hide()">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="modal-body">
    This is a first modal
    <button type="button" class="btn btn-primary" (click)="openModal2(templateNested)">Open second modal</button>
  </div>
</ng-template>

<ng-template #templateNested>
  <div class="modal-header">
    <h4 class="modal-title pull-left">Second modal</h4>
    <button type="button" class="close pull-right" aria-label="Close" (click)="modalRef2.hide()">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="modal-body">
    This is nested modal.<br>
    <button *ngIf="modalRef" type="button" class="btn btn-danger" (click)="closeFirstModal()">Close first modal</button>
  </div>
</ng-template>