suite/hr_expense_lead/views/crm_views.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <record id="crm_lead_form_opportunity_inherit" model="ir.ui.view">
        <field name="name">crm.lead.form.opportunity.inherit</field>
        <field name="model">crm.lead</field>
        <field name="inherit_id" ref="crm.crm_case_form_view_oppor"/>
        <field name="arch" type="xml">
            <xpath expr="//sheet/div[@name='button_box']" position="inside">
                <button name="%(hr_expense.hr_expense_actions_all)d" class="oe_stat_button" icon="fa-money" type="action" context="{'search_default_lead_id': active_id}">
                    <div class="o_stat_info">
                        <field name="expense_total_amount" widget="monetary" nolabel="1" options="{'currency_field': 'company_currency'}"/>
                        <span class="o_stat_text"> Expenses</span>
                    </div>
                </button>
            </xpath>
        </field>
    </record>
</odoo>