What a strong NestJS specialist actually knows
NestJS brings modules, dependency injection and decorators to Node, which suits teams larger than two. A good developer keeps modules small, uses providers for logic instead of controllers, and writes guards, pipes and interceptors that make cross-cutting rules visible.
They are fluent in TypeScript, TypeORM or Prisma, validation with class-validator and OpenAPI generation, and they know how to run NestJS as a monolith, a set of microservices over NATS or Kafka, or a GraphQL gateway.