The NSF permits foreign collaborators or CROs provided that support is only requested for the US portion of the collaborative effort. NSF may however consider cases where the foreign collaborator provides a unique and essential capability that is not available in the US. You can see NSF’s policy on Foreign Organizations here.
EGC is planning to publish a book for preparing NSF grants. We are anticipating that it will be released in Q1 2021 and available on Amazon.