This is custom alexa skill, v2 sdk
Go to Alexa Developer Console, create new custom skill, Alexa hosted (Node.js). When asked for template import the skill form this Github repository.
Then edit code in index.js, since you need to insert your url of nightscout and you have to add secret passphrase. Passphrase is written in encrypted format, you can see it in your browser console when authenticating.
alexa ask nightscout what is my sugar
alexa ask night scout to register set change
alexa ask night scout to register sensor change
alexa ask night scout to register battery change
alexa ask night scout to register new insulin