'Nodemon' is not recognized as an internal or external command

Question

I am trying to build a web scraper using JavaScript, Node.js, Express, Axios, and Cheerio. Till now I have configured package.json file and it's look like this:

{
  "name": "whatsapp-scraper",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "nodemon index.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "axios": "^1.6.7",
    "cheerio": "^1.0.0-rc.12",
    "express": "^4.17.1"
  }
}

After that I have configured the index.js file and in the file put this one of a test website to scrap the HTML of the site and the given WhatsApp chat links. The index.js file looks like this:

const PORT = 8000
const axios = require('axios')
const cheerio = require('cheerio')
const express = require('express')
const {response} = require("express");

const app = express()

const url = 'https://whatagrouplinks.com/'

axios(url)
.then(response => {
    const html = response.data
    console.log(html)
})

app.listen(PORT, () => console.log(`server running on PORT ${PORT}`))

Now after configuring the index.js file, it should return the query with the results in the form of HTML of the page and also the links. But in the terminal it's returning this code:

'nodemon' is not recognized as an internal or external command,
operable program or batch file.

Does anyone know how to fix this.