invoice_print_nota/views/qweb.xml

<?xml version="1.0" encoding="utf-8"?>
<template id="template" xml:space="preserve">
    <t t-extend="ListView.buttons">
        <t t-jquery="button.oe_list_add" t-operation="replace">
            <button t-if="widget.model == 'account.invoice'"  class="oe_button oe_new_button oe_highlight" type="button">Boton</button>
        </t>
    </t>
</template>