How do you make an alert from API become text on a webpage?

I have it set up so you have a list of countries and when you click on it it gives a pop-up with the sub region and then shows the country flag next to the country. How can I change it so that the sub region shows up with the flags using my API?

var xhttp = new XMLHttpRequest();
var respJSON = [];
xhttp.onreadystatechange = function() {
  if (this.readyState == 4 && this.status == 200) {
    resp = this.responseText;
    respJSON = JSON.parse(resp);

    html = document.getElementById("list");
    html.innerHTML = "";

    for (var i = 0; i < respJSON.length; i++) {
      html.innerHTML += "<li id=" + i + " onClick='clickMe(" + i + ")'>" + respJSON[i].name + "</li>"
    }
  }
}
//connect our api
xhttp.open("GET", "https://restcountries.com/v2/all", true);
xhttp.send();

function clickMe(index) {
  li = document.getElementById(index);
  img = document.createElement("img")
  img.src = respJSON[index].flag;
  li.append(img); 
  {
    //create subregion text on website
    //unsure how to make it show as text and not as a pop-up
    alert(respJSON[index].subregion);
  }
}