You can use this repository to test if you can use Nest CQRS on AWS lambda.

TLDR: You can't

No, it's not possible to do so because:

• Nest busses(command bus, event bus and query bus) are implemented as rxjs Observable stream
• Lambda internals do not await for Observables and contextWaitForEmptyEventLoop does nothing in this case
• After testing, it turned out that lambda quits before all events are processed and busses are empty