The Pro version of WooCommerce Product Add Ons Ultimate features the ‘checkbox groups’ field type.
With checkbox groups, you can create a group of checkboxes within a single add-on field. You can also limit the number of checkboxes, either setting a minimum number of checkboxes that must be selected, setting a maximum number, or setting a minimum and maximum number.
Create groups of checkboxes and specify the minimum and/or maximum number of checkboxes that the user should select
Please note that the checkbox group field is available on the Pro version only.