Apparently there were two Nicholas Phillips in roughly the same time frame that researchers tend to get mixed up...some even melding them into one person who married both Elizabeth Jewson and Hannah Salton. I've read the various accounts and arguments (including source citations such as Boston Baptismal records and a book called History of Weymouth by Chamberlain) and I tend to agree that they were two separate people.

A will dated Jun 2, 1671 for Nicholas who married Elizabeth Jewson, lists children Richard, Joshua, Benjamin, Alice, Experience, Hannah and Abigail. This was Nicholas Phillips of Weymouth, a deacon. (Trees show these children born bet. 1633-1662)

OUR Nicholas Phillips of Boston died 15 Mar 1670 and he was a shop keeper and "victualler". It was this Nicholas who married Hannah Salter in 1651 and had children ELIZABETH b. 1652, Hannah b. 1654, Nicholas b. 1660 and Abigail b. 1662, Sarah b. c1666 and Thomas b 1667.

Even if the birthyears of the children are not entirely accurate (because they do tend to vary from tree to tree), they obviously overlap enough to show that they could not be half siblings by two mothers...but are, much more likely, two separate families.

LATER............ I found at  The World-Wide Family of Malu Del & Tahlia Elphia McDonald information (birthplace, birthdate, more information on the birthdates of the children, and the name of Nicholas' parents (which are, of course, different from the names given for the Nicholas who married Elizabeth Jewson which were Nicholas Phillips and Abigail Sewell)