I am not researching these people, but have a booklet with some information.The Maryland Genealogical Society Bulletin, Vol. 29, #3, summer, 1988 has a "tree" on this family and several pages of information.According to this tree Nicholas was the son of Benjamin and Catherine (Sewell) Collison.Benjamin was the son of William and Sarah (Collison) Collison.William was the son of George V and Frances (Sands) Collison.George V was the son of George IV and Sarah (Aldern) Collison.George IV was the son of George IIIand Elizabeth (?) Collison.George III was the son of George II and Elizabeth (Kemp) Collison.George II was the son of George I and Elizabeth (?) Collison.George I was transported to the eastern shore about 1660.He later purchased land in Talbot County.
You could probably obtain a copy of the booklet by writing the Society at 201 West Monument St., Baltimore, MD21201.