Nested component calls in the angular project?

I think what you're looking for is EventEmitters. See https://angular.io/api/core/EventEmitter for documentation.

Here's a simple codepen to demonstrate: https://codepen.io/devmaximilian/pen/bzrKag

// parent-component.ts
@Component({
  selector: 'parent-component',
  template: `
   <h1>Parent</h1>
   <child-a-component [showNestedChild]="showNestedChildA"></child-a-component>
   <child-b-component (toggleNested)="toggleShowNestedChildA($event)"></child-b-component>
  `
})
class ParentComponent {
  showNestedChildA: boolean = false;

  public toggleShowNestedChildA(event) {
    this.showNestedChildA = !this.showNestedChildA;
  }
}

// child-a-component.ts
@Component({
  selector: 'child-a-component',
  template: `
   <h2>Child A</h2>
   <nested-child-a-component *ngIf="showNestedChild"></nested-child-a-component>
  `
})
class ChildAComponent {
  @Input() showNestedChild: boolean = false;
}

// nested-child-a-component.ts
@Component({
  selector: 'nested-child-a-component',
  template: `
  <h3>Nested Child A</h3>
  `
})
class NestedChildAComponent { }

// child-b-component.ts
@Component({
  selector: 'child-b-component',
  template: `
   <h2>Child B</h2>
   <button (click)="showNested()">Toggle Nested Child A</button>
  `
})
class ChildBComponent {
  @Output() toggleNested = new EventEmitter();

  public showNested() {
    this.toggleNested.emit(null)
  }
}