while($rows_cursos = mysqli_fetch_array($resultado_cursos)) {

$tabela1 .= '<tr>';

$tabela1 .= '<td>'.$rows_cursos['nome'].'</td>';
$tabela1 .= '<td> <input type="text" name= "Colaborador" value=""</td>';

<label for=""><h5><strong>Colaborador</strong></h5></label>
<select name="Colaborador" required>
       <option></option>
        <?php
         $servername = "xxx.xxx.x.xx";
$username = "xxxx";
$password = "xxxxxx";
$dbname = "xxxxxx";

$conn = new mysqli($servername, $username, $password, $dbname);
$conn->set_charset('utf8');

         $sql = "SELECT * FROM centrodb.colaboradores WHERE descricaovalencia = 'lar' AND estado = 1 AND Funcao = 'AAD' ORDER BY nome ASC";
         $qr = mysqli_query($conn, $sql);
         while($ln = mysqli_fetch_assoc($qr)){
            echo '<option value="'.$ln['nome'].'">'.$ln['nome'].'</option>';
         }
      ?>
    </select>

<select name="produto" id="Produto"  onchange="javascript:associaInput();"*>


function associaInput() {
    //pega o value do select
    var e = document.getElementById("Produto");
    var itemSelecionado = e.options[e.selectedIndex].value;

    //injeta no value do input
    document.getElementByName('produto.Produto').value = itemSelecionado;
}

<label for=""><h5><strong>Colaborador</strong></h5></label>
<select name="Colaborador" required>
   <option></option>

    <?php

    $servername = "xxx.xxx.x.xx";
    $username = "xxxx";
    $password = "xxxxxx";
    $dbname = "xxxxxx";

    $mysqli = new mysqli($servername, $username, $password, $dbname);


if($th = $mysqli->query("SELECT * FROM centrodb.colaboradores WHERE descricaovalencia = 'lar' AND estado = 1 AND Funcao = 'AAD' ORDER BY nome ASC");
   whiel($row = $th->fetch_assoc()){
    echo '<option value="'.$row['nome'].'">'.$row['nome'].'</option>';

   }

  ?>
</select>