Dean, here's the setup you should use:
Call this page with a microflow. In that microflow, create a Supplier and Contact, set the contact's association to the new supplier and use the Open Page activity to open your page, passing in the new Contact.
Then on the page: use a Contact dataview (passed from caller of the page). Inside that, add a nested dataview for the supplier.
Did you try to set the association between the two objects? So create a supplier and a contact and make sure that the association is set in either the contact or supplier create action (depending on the model) and then opening the form with in this case passing the supplier.
Fantastic. Thank you. It was setting the association between the two new objects in the microflow that I didn't get. Never done that before. I think that is what Erwin was getting at also and I didn't understand.