JSFiddle - React, Tailwind, and code Playground

HTML

<p><input type="text" placeholder="Ник игрока" id="nickname"></p>
<p><input type="text" placeholder="Ник игрока еще раз" id="lkeys"></p>

JavaScript

$(function(){
	var $nickname = $('#nickname');
	var $lkeys = $('#lkeys');
	$nickname.on('change keyup keydown focus blur', function(event){
		var nickname = $nickname.val();
		$lkeys.val(nickname);
	})
});