@platypusrex2018 I checked your site, it is the “Multi-Step Checkout for WooCommerce” plugin that hides the payment area when the checkout page loads. So when the NMI’s card fields (via the Collect.js library) are mounted it cannot detect the height of the container. You can switch to the checkout tabs element built in Avada, since we have added compatibility for it in the past: https://avada.com/documentation/woo-checkout-tabs-element/
If that does not work, you can just remove the NMI tokenization key from the plugin settings page and it will switch to the direct post method, and WooCommerce’s built-in card fields will then appear.