I want to scrape the second page of this user reviews.
However the next button executes a XHR request, and while I can see it using Chrome developer tools, I cannot replicate it.
It's not so easy task. First of all you should install this extension. It helps you to test own requests based on captured data, i.e. catch and simulate requests with captured data.
As I see they send a token in this XHR request, so you need to get it in from html page body(stores in source code, js variable "taSecureToken" ).
Next you need to do four steps:
offsetvariables in POST request data
Note: on this request server returns json data(not the html with next page) containing info about loaded objects on next page.