WikiTree does DNA matching via the GEDmatch.com and mitoYDNA.org databases. WikiTree does not store raw DNA. Autosomal DNA (and X chromosomes) are uploaded to GEDmatch.com and Y chromosomes (Y-DNA) and mitochondrial DNA (mtDNA) are uploaded to mitoYDNA.org. Then the testee adds their GEDmatch ID and/or mitoYDNA ID to their DNA Tests page at HTTPs://www.wikitree.com/wiki/Special:DNATests
These videos demonstrate how DNA matching and comparisons work via WikiTree:
Find your autosomal DNA matches in GEDmatch via WikiTree:
https://m.youtube.com/watch?v=b6yeCirkINc
Find your autosomal DNA matches in WikiTree:
https://m.youtube.com/watch?v=1NgD9b3s0Gs
Compare two autosomal DNA testees in GEDmatch via WikiTree:
https://m.youtube.com/watch?v=0FYhIZKGwlY
Find your X chromosome matches in WikiTree:
https://m.youtube.com/watch?v=wcoJppPcI6k
Find X chromosome tested descendants in WikiTree and compare their X chromosomes:
https://m.youtube.com/watch?v=Qva7RYzYTVQ
Find your X chromosome matches in GEDmatch via WikiTree:
Compare Y-DNA via WikiTree:
https://m.youtube.com/watch?v=qP1U_K_FEEE
Compare mtDNA via WikiTree:
https://m.youtube.com/watch?v=ZCHSFtSMjY8
GEDmatch and mitoYDNA are free (like WikiTree).
As far as I know, only Y-DNA and mtDNA testing was done on Nicholas’ remains. A male who has tested with AncestryDNA can use a utility to get their basic Y haplogroup
see https://www.wikitree.com/g2g/800267/are-you-a-male-who-has-tested-with-ancestrydna
and males who tested with 23andMe or Living DNA will get their Y haplogroups, but Nicholas’ Y halogroup is only an estimate for his basic haplogroup.