[Plugin: Easy Popular Posts] From specific category

Yes, modify the query in the plugin code:

global $wpdb;
$posts = $wpdb->get_results("
SELECT comment_count, ID, post_title
FROM $wpdb->posts wposts
LEFT JOIN $wpdb->term_relationships ON (wposts.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
WHERE $wpdb->term_taxonomy.taxonomy = 'category'
AND $wpdb->term_taxonomy.term_id IN($my_category_id)
AND post_type='post' AND post_status = 'publish' AND comment_count >= " . $ns_options['comments']."
		" . $sqlorder . " LIMIT 0 , " . $ns_options['count']
	);