Hello,

You can check with this command found on this website: https://unmitigatedrisk.com/?p=100
openssl s_client -connect login.live.com:443 -tls1 -tlsextdebug -status

If everything goes well, you should find something like:
"OCSP response:
======================================
OCSP Response Data:
OCSP Response Status: successful (0x0)
Response Type: Basic OCSP Response
..."

If there's no stapling, you'll get:
"OCSP response: no response sent".

Please note: when you restart nginx, you won't get an OCSP answer immediatly. You'll have to visit the URL and wait a few seconds before having the stapling working for the next request. IIRC, this behavior is because OCSP servers may be slow to answer.

Best Regards