No it won't, unless you're doing something stupid in your app, such as using synchronous or CPU-heavy code. But putting nginx in front of it doesn't save you he

No it won't, unless you're doing something stupid in your app, such as using synchronous or CPU-heavy code. But putting nginx in front of it doesn't save you here either; you'd need a caching reverse proxy instead. The only thing where nginx might help performance-wise here is static file access (of eg. static web assets such as CSS or static HTML).