App.html

<p>This is a top-level element.</p>
<Nested on:event1=event1(event) on:event2:1=event21(event)/>

<script>
	import Nested from './Nested.html';

	export default {
		methods: {
			event1(event) {
				console.debug('event1')
			},
			event21(event) {
				console.debug('event2:1')
			}
		},
		components: {
			Nested
		}
	};
</script>

Nested.html

<p>And this is a nested component.</p>

<script>
	export default {
		oncreate() {
			this.fire('event2:1')
			this.fire('event1')
			console.debug('oncreate')
		}
	};
</script>