I did some checking in a book of historic atlases, but the results were inconclusive (but see the map link below, which I later found. I was looking for evidence that Hudson Bay was charted prior to its 'discovery' in 1610, which would suggest that mapmakers were acquainted with Nicholas/Cnoyen's work, and if properly placed would suggest that Nicholas was where he should have been if the KRS (and Knudson/Nicholas link) were true.

Most maps show no information about the NE coast of N. America - in particular such maps as drawn by those from southern Europe. Northern european maps tended to be a little better in this regard. The Ruysch map of 1508 shows a large bay south of the Artctic in the proper location, in relation to Northern Europe, but it seems to be a little too far north. He places (as do several others) the four islands with the four channels directly surrounding the North pole, and not in Hudson strait which is where they should be. It is rather interesting to note that this map was drawn before it was known that America is a separate continenent, and so seems to be placed just NE of China.

Gerard Mercator in 1538, also shows a bay to the North of China, in very much the wrong place, but of the right size and dimension to be Hudson Bay. It is interesting to note here that there is a long channel extending to the east for quite some distance while the area to the west is left blank. This would suggest that Mercator got his information from a source of someone traveling westward along the coastline, rather than from an exploration from the south or east. Fianally there is the Rumold Mercator circumpolar map of 1595. This does have a large circular bay in central Canada, its mouth just below the arctic circle. It also has the four great Islands surrounding the north pole with the four channels as mentioned before.
Ah well, as I say though some of these maps are very tempting, none of them are conclusive.

Update: See the link in the next article for an early map which seem to clearly show Hudson Bay