NestJS adds about 17 microseconds per request on Express and about 9 on Fastify, measured against raw Node.js at 14.7 and Express 5 at 65.2.
On one validated JSON endpoint raw Node.js served 68,156 requests per second, Fastify 69,717, NestJS on Fastify 43,412, Express 5 15,332 and NestJS on Express 12,170.
With a 5 millisecond awaited dependency all variants served 7,450 to 8,150 requests per second at a 6 millisecond median, so pick on structure and team size.