Both the 1926 ship's passenger list and the 1930 US census sheet show Nicholas Holland as married. The census sheet indicates that he married about 1923, but in the event, I think the following has to be a candidate for the marriage, it took place in 1921 to a Mary Ellen Mathews - although the groom's father is given as 'Patrick Joseph', the groom's occupation and address are right on the money:
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1921/09241/5344946.pdfFurthermore, the 1926 passenger list shows Nicholas intending to join a Michael Mathews of 31 Montrose St. in Sommerville, Massachusetts. Although Michael is described as 'B.I.N.', I think that is a typo and is meant to be 'B.I.L.' (which appears elsewhere on the same page, ie. brother-in-law).
Edited to add: The other 1926 passenger list showing Nicholas' name stroked out has a comment at the bottom to say that he cancelled and did not sail, but that comment too is stroked out, so I'm guessing that he didn't cancel after all. Anyhow, this other passenger list is useful, for this time it shows his nearest relative as 'Mrs. Mary E. Holland, Blackrock, Dundalk' and it confirms the person he was going to join in the USA as 'Brother-in-law, Mr. M Mathews'.
The following looks like Mary Ellen's grave, so I'm not sure if she ever followed Nicholas across the Atlantic, also below is her 1967 death registration - note that a Drogheda newspaper of 1981 mentions someone with that surname at that same (death registration) address, so maybe Nicholas and Mary Ellen had children:
https://billiongraves.com/grave/Mary-E-MATHEWS-HOLLAND/10592379https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1967/04213/4077498.pdf
