The theme developer provided a resolution using javascript. It can be found below if anyone is hunting for a similar solution:

<script>
jQuery(document).ready(function($){
function getQueryParams(qs) {
qs = qs.split("+").join(" ");
var params = {},
tokens,
re = /[?&]?([^=]+)=([^&]*)/g;
while (tokens = re.exec(qs)) {
params[decodeURIComponent(tokens[1])] = decodeURIComponent(tokens[2]);
}
return params;
}
       
setTimeout(function(){
      if( $('.woocommerce-account').length > 0 ) {
var nectarGetQueryParam = getQueryParams(document.location.search);
if (typeof nectarGetQueryParam['tab'] != 'undefined' && nectarGetQueryParam['tab'] == 'register' ) {
           $('.nectar-form-controls .control:last-child').trigger('click');
        }
}
},200);
});
</script>