let str = "Only one message at a time. Please allow any other responses to complete before sending another message, or wait one minute.";

function contains(selector, text) {
    const elements = document.querySelectorAll(selector);
    return Array.prototype.filter.call(elements, function (element) {
        return RegExp(text).test(element.textContent);
    });
}

setInterval(() => {
    if (document.body.innerText.indexOf(str) > 0) {
        contains("button", "Regenerate")[0].click();
    }
}, 2000);