There are 22 "Smart Matches" for Nicolass Van Slyck, all 22 give his parents as Cornelius Antonissen van Slyck and Ots-Toch Hartell. They predominantly list his birth as 1791 and death as 1864.
Considering Ots-Toch died in 1646 and her husband, Cornelius, was borth c.1600 there is no way Nicolass could be there son.
I cannot think of polite to say so i will just sever the relationship and leave Nicolaas to float free for the time being.
If the connections on your tree are accurately placed then if you are Dutch, you really have no choice in the matter. I am sure each ethnicity has something of interest that one can learn of.
Dutch painters are quite important in art history. One the big tree we cannot just pick and choose who we want to be related to. Maybe embrace the new found link.
Good luck.