It is true that major glacial activity occurred repeatedly during the Pleistocene east of the Hudson Bay (eg: Laurentidian Ice Sheet sweeping again and again), but yet the Chicxulub impact was subject to many factors of erosion as well since its formation near the K-T boundary.
Still these kind of surveys indicate the nature of the material in the crust - so even if several glaciations impacted the Nastapoka arc area, there would be some kind of patterns still present indicating heavy metals (Chondrite or anything typical of an impact, iron or circular metamorphism).
To conclude, unless other surveys suggests an alternative interpretation path in the future, few evidences strongly support the theory of an ancient impact at Nastapoka.