I sent the question as posted here to the CBP (because noone sources their answers and it reads to me as beliefs held about passports not facts) and received the information below. Based on this, despite it is not a straight yes or no (they never do that) I believe I am allowed to present a Canadian passport because otherwise why would they point out what happens if I present one. I will seek further clarification in April once I get my passport and add it to my NEXUS at the NEXUS centre but for now I think I am good.
So, without further ado, their reply:
Thank you for contacting the U.S. Customs and Border Protection (CBP) INFO Center.
A Canadian citizen does not need a visa to visit the United States.
If you present a Hungarian passport: https://help.cbp.gov/app/answers/detail/a_id/572
If you present a Canadian passport: https://help.cbp.gov/app/answers/detail/a_id/619
If you have any other questions or concerns, please feel free to call our toll-free number 877-CBP-5511 (877-227-5511). From outside the United States, please call 202-325-8000 - you may incur charges from your telephone service provider for this call. Our service hours are Monday through Friday from 9 a.m.-4 p.m. Eastern Time. We are closed on all U.S. federal holidays.
We hope our answers ease your entry into the United States. Please understand these answers are informational only, The CBP officer who speaks with you upon arrival determines the admissibility of goods and visitors.
Thank you again for contacting the CBP INFO Center.
CBP INFO Center