Yes, you can add multiple 123 Form Builder forms to the exact same Wix site.
If this is your first time publishing a 123 Form Builder form on Wix, go to your Wix website editor. Then open the Add Apps section of your site and add the 123 Form Builder app.
If you need to publish a second form, all you need to do is search again for our form builder app in the Wix App Market. Afterward, click on Add Again. The publish method is the same.