Yes, The N-Tester BT can be used in conjunction with Atfarm to give you variety-specific nitrogen recommendations in the field. Yara recommends using the N-Tester on winter cereals between GS31 and GS51 to help fine-tune the final nitrogen application.
Simply take the measurements in the field using the N-Tester then use Atfarm to get the nitrogen recommendation.
Find more information on Atfarm or the N-Tester BT