Can IFR-certified GPS be used to substitute for NDBs in Canada when
navigating an airway?

I'm a US-certificated pilot flying a US-registered plane. I'd like to
take advantage of lower MEAs in western Canada provided by airways.
Many of the airways appear to be between NDBs. If my ADF is known inop
(or my plane doesn't have an ADF), can I use the panel-mount Garmin 430
as a substitute?