Hello @kartik,
Edit package.json and remove the ./.
Change
"start": "./node_modules/nodemon/bin/nodemon.js src/app.js"
to
"start": "nodemon src/app.js"
Alternatively, you can try:
npm install -g nodemon
and change the start command to
"start": "./node_modules/nodemon/bin/nodemon.js src/app.js"
Thank You!!