If you wanted to hand craft this you could use the Scriptrunner JIRA add on to perform a Monday API call for a certain event.
You can get the comments from a simple GET:
def issueKey = 'DEMO-1'
def result = get('/rest/api/2/issue/' + issueKey)
.header('Content-Type', 'application/json')
.asObject(Map)
return result.body.fields.comment.comments
The above returns the comments as JSON.
I’ve got an example of using a Post Function to create a pulse here - Using the API to create a pulse with JIRA ticket details from a JIRA state change - #4 by AlexSavchuk