Deploying NestJS application on Elastic Beanstalk via Code pipeline

buildspec.yml

# Do not change version. This is the version of aws buildspec, not the version of your buldspec file.
version: 0.2

phases:
  install:
    runtime-versions:
      nodejs: '12'
  pre_build:
    commands:
      - echo Installing source NPM dependencies...
      - npm install
  build:
    commands:
      - echo Build started on `date`
      - echo Running build...
      - npm run build
  post_build:
    commands:
      - echo Build completed on `date`
artifacts:  
  files:  
    - "**/*"

Package.json should have start command as "start": "node dist/main

{
  "name": "nest-test",
  "version": "0.0.1",
  "description": "nest.js testing",
  "author": "Vikash Rathee",
  "scripts": {
    "prebuild": "rimraf dist",
    "build": "nest build",
    "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
    "start": "node dist/main",
    "start:dev": "nest start --watch",
    "start:debug": "nest start --debug --watch",
    "start:prod": "node dist/main",
    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
    "test": "jest",
    "test:watch": "jest --watch",
    "test:cov": "jest --coverage",
    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
    "test:e2e": "jest --config ./test/jest-e2e.json"
  },
}