we have a customer that has many users but they can only ship to one address & send invoice to one address (both different). there doesn't seem to be a way in NopCommerce to restrict this or even remove the ability to remove the option of "Add New Address" on the checkout screen.
Customization is needed. nopCommerce does not have a way to indicate that an address is only a billing or shipping address. Also, there is no ability (ACL / Access Control List / Permission) to suppress adding a new address.
(Shipping Director can be configured to prevent the checkout from continuing if it detects improperly selected addresses, but it only can check at the point of the shipping methods/rate selection page, and would have to have a rule for each customer you want to check.)